Markers for pre-cancer and cancer cells and the method to interfere with cell proliferation therein

ABSTRACT

A novel family of human mitochondrial RNAs, referred to as chimeric RNAs, which are differentially expressed in normal, pre-cancer and cancer cells, are described. Oligonucleotides targeted to the chimeric RNAs are provided. The described oligonucleotides or their analogs can be used for cancer diagnostics and cancer therapy as well as for research. In one embodiment of this invention, these oligonucleotides hybridize with the sense or with the antisense mitochondrial chimeric RNAs, and the result of the hybridization is useful to differentiate between normal proliferating cells, pre-cancer cells and cancer cells. In another embodiment of the invention, the compositions comprise oligonucleotides that hybridize with the human chimeric RNAs resulting in cancer cell and pre-cancer cell death, while there is no effect in normal cells, constituting therefore, a novel approach for cancer therapy.

RELATED APPLICATION DATA

This application is a 35 U.S.C. §371 continuation of Internationalapplication no. PCT/US2004/015929, which, in turn, claims the benefit ofU.S. Provisional application No. 60/472,106, filed May 21, 2003, under35 U.S.C. §119(e) and 365.

REFERENCE TO SEQUENCE LISTING

This application hereby incorporates by reference, in its entirety, thesequence listing on a single compact disc, in the file entitled,“Sequence Listing.ST25.TXT” which was created and recorded on May 17,2006, and is 43 kilobytes in size.

FIELD OF THE INVENTION

The invention relates to cancer therapy, cancer diagnosis and researchreagents in connection with a novel family of human mitochondrial RNAsreferred to as human mitochondrial chimeric RNAs. In particular, thisinvention relates to oligonucleotides targeted to the humanmitochondrial chimeric RNAs. The oligonucleotides of the inventionhybridize to the chimeric RNAs inducing cancer cell death. Thecomposition and methods provided in the invention are useful as a newcancer therapy. In addition, the oligonucleotides can be used fordiagnosis of cancer and pre-cancer cells based on the differentialexpression of the mitochondrial chimeric RNAs in resting andproliferating normal cell, pre-cancer and cancer cells.

BACKGROUND OF THE INVENTION

Mitochondria

Mitochondria are subcellular organelles that manufacture the essentialmolecule adenosine triphosphate (ATP) by oxidative phosphorylation. Thehuman mitochondrial DNA (mtDNA) of 16,654 base pair encodes tworibosomal RNAs, 22 transfer RNAs (tRNAs) and 13 open reading frames(ORF) that encode a similar number of polypeptides (Clayton, Hum Reprod.Suppl 2:11-17, 2000; Taanman, Biochim. Biophys. Acta, 1410:103-123,1999). On the basis of the content of G+T base composition, the twostrands of the mtDNA differ in buoyant density and can be separated indenaturating cesium chloride gradients. The heavy strand or H-strandencodes the two ribosomal RNAs (12S and 16S), 14 tRNAs and 12polypeptides corresponding to ND 1, ND 2, ND 3, ND4L, ND4, ND 5, COX I,COX II, COX III, ATP6, ATP8 and Cyt b. The light strand or L-strandcodes for 8 tRNAs and the subunit of the complex NAD dehydrogenase ND6(Clayton, Hum Reprod. Suppl 2:11-17, 2000; Taanman, Biochim. Biophys.Acta, 1410:103-123, 1999).

A large proportion of the mtDNA contains a short three-strandedstructure called the displacement loop or D-loop. This region, that inhumans is 1,006 base pairs, is flanked by the genes for tRNA ofphenylalanine (tRNA^(Phe)) and the tRNA of proline (tRNA^(Pro)) andcontains a short nucleic acid strand complementary to the L-strand anddisplacing the H-strand (Clayton, Hum Reprod. Suppl 2:11-17, 2000;Taanman, Biochim. Biophys. Acta, 1410:103-123, 1999). This region hasevolved as the major control site for mtDNA expression and contains theleading-strand or H-strand origin of replication and the major promotersfor transcription of the H-(HSP) and L-strand (LSP). Despite the closeproximity of the HSP and LSP (about 150 bp), these regulatory elementsare functionally independent in vitro (Shuey and Attardi, J Biol Chem.260:1952-1958, 1985; Taanman, Biochim. Biophys. Acta, 1410:103-123,1999) as well as in vivo, utilizing model of patients with mitochondrialdiseases (Chinnery and Turnbull, Mol. Med. Today, 6:425432, 2000).

Both strands are transcribed as polycistronic RNAs which are thenprocessed to release the individual mRNAs, tRNAs and the rRNAs (Taanman,Biochim. Biophys. Acta, 1410:103-123, 1999). In humans, themitochondrial RNA polymerase is a protein of 1,230 amino acids withsignificant homology with the sequence of yeast mitochondrial RNApolymerase and with the RNA polymerases of several bacteriophages(Tiranti et al., Hum Mol Genet. 6:615-625, 1997). In addition, a familyof transcription factors have been characterized such as themitochondrial transcription factor A or TFAM which is essential formammalian mtDNA transcription and is a member of the high mobility group(HMG)-box family of DNA-binding proteins (Parisi and Clayton, Science.252:965-969, 1991). Recently, two independent reports described thecharacteristics of new transcription factors, TFB1M and TFB2M, in humanand mouse (McCulloch et al., Mol. Cell Biol. 22:1116-1125, 2002;Falkenberg et al., Nat Genet. 31:289-294, 2002; Rantanen et al., MammGenome. 14:1-6, 2003). In spite of the considerable progress achieved onthe cis- and trans-acting elements involved in mtDNA transcription, thefunctional details are not fully understood.

Mitochondria and Apoptosis

Mitochondria play a central role in apoptosis, a fundamental biologicalprocess by which cells die in a well-controlled or programmed manner.This cell suicide program is essential during development and for adulthomeostasis of all metazoan animals. Apoptosis is activated to eradicatesuperfluous, damaged, mutated and aged cells (Meier et al., Nature407:796-801, 2000). Disregulation of apoptosis is implicated in theappearance of several pathologies. Thus, abnormal inhibition ofapoptosis is a hallmark of neoplasia, whereas massive apoptosis has beenlinked with acute diseases such as stroke, septic shock andneurodegerative disorders. At present the process of apoptosis isdescribed as two major pathways known as the extrinsic and the intrinsicpathways (Zörnig et al., Biochim. Biophys. Acta, 1551:F1-F37, 2001). Theextrinsic pathway is a process that is initiated at the cell membrane bythe binding of different ligands to the death receptors (Krammer, Nature407:789-795, 2000; Zörnig et al., Biochim. Biophys. Acta, 1551:F1-f37,2001).

Caspases, are responsible for the proteolytic cascade in apoptosis.Caspases are synthesized as inactive precursor proteins that undergoproteolytic maturation or processing upon apoptosis induction (Zörnig etal., Biochim. Biophys. Acta, 1551:F1-F37, 2001). However, more recentlyseveral experimental evidences indicate that lysosomal proteasesconstitute an alternative pathway of proteolysis after apoptotic insults(Guicciardi et al., Oncogene, 23:2881-2890, 2004).

On the other hand, anti-apoptotic proteins homologous to the humanoncoprotein Bcl-2 have been described. This protein belongs to a familyof proteins that are either anti-apoptotic (Bcl-2, Bcl-XL, Bcl-w) orpro-apoptotic (Bax, Bak, Bim, Bid, etc.) (Zörning et al., Biochim.Biophys. Acta, 1551:F1-F37, 2001).

Mitochondria are particularly affected early during the apoptoticprocess and at present time they are recognized as the centralcoordinators of cell death (Boya et al., Biochem. Biophys. Res. Commun.304:575-581, 2003; Ferri and Kroemer, Nature Cell Biol. 3:E255-E263,2001; Zörnig et al., Biochim. Biophys. Acta, 1551:F1-F37, 2001). Severalpro-apoptotic signal and damage pathways converge on mitochondria toinduce mitochondrial membrane permeabilization, phenomenon that is underthe control of Bcl-2 proteins (Boya et al., Biochem. Biophys. Res.Commun. 304:575-581, 2003; Zörnig et al., Biochim. Biophys. Acta,1551:F1-F37, 2001). After cells receive apoptotic insults, thetrans-membrane potential (Δψ_(m)) dissipates resulting in the completepermeabilization of the outer mitochondrial membrane and the consequentleakage of toxic mitochondrial intermembrane proteins. The first exampleof the leakage of a mitochondrial protein was the liberation ofcytochrome c (Liu et al., Apoptosis, 6:453-462, 2001). When cytochrome cis present in the cytosol, it drives the assembly of the caspaseactivating complex termed the apoptosome. Cytochrome c binds to Apaf-1(apoptotic protease activatin factor-1) facilitating the binding ofdATP/ATP to the complex and the oligomerization of Apaf-1 (Adrain etal., 1999; Benedict et al., 2000). Oligomerization of Apaf-1 allows therecruitment of pro-caspase-9 which catalyzes the proteolytic activationof the precursor and generation of active caspase-9 (Adrain et al., J.Biol. Chem. 274:20855-20860, 1999; Benedict et al., J. Biol. Chem.,275:8461-8468, 2000).

A family of cytosolic inhibitor of apoptosis proteins have beendescribed and are known as XIAP, c-IAP1 and c-IAP2. These proteins bindto and inhibit processed caspase-3 and caspase-9 and consequently stopthe cascade of degradation. However, the cell also contains counterminemechanisms to bypass this anti-apoptotic pathway. In cells undergoingapoptosis, caspases are liberated of this inhibitory effect by bindingto IAPs of a protein known as Smac (Second Mitochondrial Activator ofCaspases) or DIABLO (Direct IAP Binding protein with Low pl) (Verhagenet al., Apoptosis, 7:163-166, 2002). By binding to IAPs, Smac/DIABLOdisplace active caspases from IAPs and thus promote cell death. Anotherprotein, knowns as HtrA2, is released from the mitochondria into thecytosol after apoptotic insult where the protein binds to IAPs in asimilar fashion as does Smac/DIABLO and thereby facilitating caspasesactivation (Verhagen et al., Apoptosis, 7:163-166, 2002; Martins et al.,2001; Suzuki et al., Mol. Cell, 8:613-621, 2001; Hedge et al.,Apoptosis, 7:123-132, 2002).

The apoptosis inducing factor (AIF) is another component of theapoptotic cascade. After induction of apoptosis, AIF translocates to thecytosol and to the nucleus. In the nucleus, AIF induces peripheralchromatin condensation and DNA fragmentation. AIF also induces severalhallmarks of apoptosis like Δψ_(m) dissipation and phosphatidylserineexposure (Zörnig et al., Biochim. Biophys. Acta, 1551:F1-F37, 2001). Afactor that seems to regulate the apoptotic activity of AIF is the heatschock protein 70 (Ravagnan et al., Nature Cell Biol. 3:839-843, 2001).Another mitochondrial factor that exits the mitochondria andtranslocates into the nucleus like AIF is endonuclease G or Endo G. Inthe nucleus, Endo G generates DNA fragmentation even in the presence ofcaspase inhibitors (Li et al., Nature, 412:95-99, 2001). Endo G may actin similar fashion as CAD (caspase-activated DNAse), a nuclease whoseactivation critically relies on caspases (Samejima et al., J. Biol.Chem., 276:45427-45432, 2001).

Cancer and Pre-Cancer

Cancer is a cellular malignancy whose unique trait, loss of normalcontrol of cell cycle, results in unregulated growth, lack ofdifferentiation, and ability to invade other tissues and metastasize.Carcinogenesis is the process by which a normal cell is transformed in amalignant cell. Carcinogenesis is a multiple step process beginning withthe genetic event of initiation followed by selective expansion ofaltered cells during promotion to form early adenomas. In the absence ofcontinuous promotion, the adenoma regresses and disappears. With asecond genetic event, a small number of promoted adenomas progress toform late adenomas some of which may then undergo malignant conversion(McKinnell et al., “The Biology Basis of Cancer”, Ch. 3, 1998).

The etiology of cancer is complex and includes alteration of the cellcycle regulation, chromosomal abnormalities and chromosomes breakage.Infectious agents such several types of oncogenic viruses, chemicals,radiation (ultraviolet or ionizing radiation) and immunologicaldisorders are thought to be the major causes of carcinogenesis(McKinnell et al., “The Biological Basis of Cancer, Ch.3, 1998).

It has been proposed for a long time that cancer is also related tomitochondrial dysfunction. One of these theories suggests thatmitochondrial mutation might be the primary cause of cell transformationand cancer (Warburg, 1956; Carew and Huang, Mol. Cancer, 1:1-12, 2002).Alterations of the mitochondrial DNA (mtDNA) was reported in hematologicmalignancies (Clayton and Vinograd, Nature, 216:652-657, 1967) and inbreast cancer (Tan et al., 2002; Parrella et al., 2001). Mutations ofseveral regions of the mtDNA and deletions have been also identified inpatients with colorectal cancer, prostate cancer, ovarian cancer,gastric cancer, pancreatic cancer, hepatocellular carcinoma, esophagealcancer, kidney cancer, thyroid cancer and brain tumors (reviewed byCarew and Huang, Mol. Cancer, 1:1-12, 2002). In general, there appearsto be two major features of mtDNA alterations in cancer irrespective oftumor type. The majority of the mutations are base transitions from T toC and G to A. Second, while there is diversity in the particular genesin which mutations occur, the D-loop seems to be the most frequentsomatic mutated region of the mtDNA in most tumor types.

Pre-cancer cells are defined here as a transformed cell which can evolveor differentiate into a malignant cell. Some examples are cellstransformed by DNA or RNA oncoviruses.

The present invention is related to a novel family of mitocondrial RNAsand the use herein of these RNAs as targets for diagnostics and cancertherapy. The present invention provides compositions and methods andthat are useful to differentiate normal cells from tumor cells, or frompre-malignant cells or cells transformed with oncogenic viruses. Inparticular, as elaborated below, the present invention providescomposition and methods for diagnostic assays to differentiate normalcells from pre-cancer and cancer cells. In another embodiment of theinvention, composition and methods are provided to induce massive andselective tumor cell death. Therefore, the present invention providescompositions and methods which may be used in cancer and pre-cancerdiagnostic and therapy as well as for research.

SUMMARY OF THE INVENTION

The present invention is directed to compositions and methods useful fordetecting a family of novel human mitochondrial RNAs, referred to asmitochondrial chimeric RNAs, that are expressed differentially in normalresting and proliferating cells, pre-cancer and cancer cells.

Sense Mitochondrial Chimeric RNAs

In one aspect of this invention compositions and methods are provided todetect a mitochondrial chimeric RNA comprised of an inverted repeat of815 nucleotides joined covalently to the 5′ end of the 16S mitocondrialribosomal RNA (SEQ ID NO 1). The inverted repeat corresponds to afragment of 815 nucleotides of the RNA transcribed from the L-strand ofthe 16S gene of the mtDNA. Thus, the synthesis of this novel RNArequires the transcription of the L-strand and the H-strand of the 16Sgene of the mtDNA. Since transcription of both strands of the mtDNA areregulated by different promoters, we refer to this novel RNA in thepresent invention as the mitochondrial chimeric RNA (SEQ ID NO 1). Inaddition, since the inverted repeat of 815 nucleotides is joined to the“sense” 16S RNA (transcribed from the H-strand) we refer to this novelRNA as the “sense mitochondrial chimeric RNA”

This invention provides methods and compositions to detect theexpression of the sense mitochondrial chimeric RNA in cultured cells, incell samples, and in tissue sections. The detection can be carried outby in situ hybridization, synthesis of the corresponding cDNA andamplification by PCR, transcription mediated amplification (TMA)(Comanor et al., J. Clin Virol., 28:14-26, 2003) or Northern blot, orother methods obvious to one skilled in the art.

In one aspect of this invention, in situ hybridization assays revealedthat the sense mitochondrial chimeric RNA is expressed in normalproliferating cells, in tumor cells in culture as well as in tumor cellspresent in human biopsies of different tumor types. The sensemitochondrial chimeric RNA is not expressed in normal resting cells. Inyet another embodiment of the invention, methods and compositions areprovided to detect a second novel sense mitochondrial chimeric RNA incells transformed with papilloma virus 16 or 18 (Hausen, Biochim.Biophys. Acta, 1288:F55-F78, 1996). In these transformed cells, a newsense mitochondrial chimeric RNA comprising of an inverted repeat of 754nucleotides joined covalently to the 5′ end of the 16S mitochondrial RNAis expressed (SEQ ID NO 2). This RNA is not present in normalproliferating cells or in tumor cells. The methods and compositions alsodemonstrated that a third sense mitochondrial chimeric RNA, comprisingan inverted repeat of 694 nucleotides joined covalently to the 5′ end ofthe 16S mitochondrial RNA (SEQ ID NO 3), is present in cells transformedwith HTLV-1.

Antisense Mitochondrial Chimeric RNA

This invention also provides methods and compositions that revealed thatnormal proliferating cells over express an antisense mitochondrialchimeric RNAs corresponding to SEQ ID NO 4, SEQ ID NO 5, SEQ ID NO 6.These transcripts contain inverted repeats of variable length(transcribed from the H-strand) joined to the 5′ end of the antisense16S mitochondrial ribosomal RNA (transcribed from the L-strand), hencethe name of antisense mitochondrial chimeric RNA. The expression of theantisense mitochondrial chimeric RNA is down regulated in tumor celllines in culture as well as in tumor cells present in human biopsies ofdifferent types of tumors as well as in transformed or pre-cancer cells.Accordingly, the present invention provides methods and composition todetect the expression of the sense and the antisense mitochondrialchimeric RNAs, distinguishing normal proliferating cells from cancer andpre-cancer cells and therefore provides a novel marker for malignantcells and cancer.

Cancer Therapy

In another aspect of this invention, methods and compositions areprovided to interfere with the sense and antisense mitochondrialchimeric RNAs. One preferred embodiment is to interfere with theantisense mitochondrial chimeric RNA in tumor cells which contains lowcopy number of this transcript. The interference is carried out witholigonucleotides or oligonucleotide analogs, whose sequences arecomplementary to the sequences of the antisense mitochondrial chimericRNA (SEQ ID NO 4 and/or SEQ ID NO 5 and/or SEQ ID NO 6). Treatment oftumor cells of different types with one or more of these complementaryoligonucleotides induces cell death or apoptosis. The oligonucleotidesare compounds of 15 to 50 nucleotides where at least 15 nucleobases arecomplementary to SEQ ID NO 4 and/or SEQ ID NO 5 and/or SEQ ID NO 6.Examples of these complementary oligonucleotides are shown in SEQ ID NOS9 to 97. The induction of apoptosis is selective since treatment ofhuman lymphocytes (normal resting cell) or human lymphocytes stimulatedwith phytohaemagglutinin (normal proliferating cells) do not undergoapoptosis after treatment with oligonucleotides complementary to thesequences of the antisense mitochondrial chimeric RNA under the sameconditions. If the tumor cells are treated with oligonucleotidestargeted or complementary to the sense mitochondrial chimeric RNA (SEQID NO 1 and/or SEQ ID NO 2 and/or SEQ ID NO 3) a diminished induction ofcell death or apoptosis is obtained.

BRIEF DESCRIPTION OF THE DRAWING

FIGS. 1A, B and C. Line drawings showing the structure of sensemitochondrial chimeric RNAs corresponding to SEQ ID NO 1, SEQ ID NO 2and SEQ ID NO 3. The arrows indicate the relative position of theprimers used to amplify the RNA by pieces. The arrows below the linesare reverse primers, and the arrows on top of the lines are forwardprimers. Primer 1 is positioned close to the 5′ end of the 16Smitochondrial RNA. The Black lines correspond to the sense 16Smitochondrial RNA, while the doted lines correspond to the antisense 16Smitochondrial RNA.

FIG. 2. Agarose gel electrophoresis to show the amplification productobtained between primer 1 and primer 3 indicated in FIG. 1A. Theamplification was carried out by RT-PCR using as template a tumor cell(SiHa), human keratinocytes transformed with HPV 16 (HFK698) orB-lymphocytes transformed with HTLV-1. With RNA from SiHa cells only onesingle amplicon of 210 bp was obtained and corresponds to a segment ofSEQ ID NO 1. In total RNA of keratinocytes transformed with HPV 16,besides the amplicon of 210 bp, a second amplicon of 150 bp was obtainedand corresponds to a segment of SEQ ID NO 2. With RNA from cellstransformed with HTLV-1, besides the amplicons of 210 bp and 150 bp, athird amplicon was obtained and corresponds to a segment of SEQ ID NO 3.

FIG. 3. Line drawings showing the structure of the antisensemitochondrial chimeric RNAs corresponding to SEQ ID NO 4, SEQ ID NO 5and SEQ ID NO 6. The arrows represent the primer used for amplification,and primer 1 is positioned close to the 5′ end of the antisense 16Smitochondrial RNA. The strategy to obtain the sequence of thesetranscripts is similar to that described in FIG. 1.

FIGS. 4A and 4B. In situ hybridization assays carried out with severaltumor cell lines in culture. The cells were hybridized witholigonucleotide probes complementary to the sense mitochondrial chimericRNA, and labeled with digoxigenin (left panels). In addition, the cellswere also hybridized in parallel with oligonucleotide probescomplementary to the antisense mitochondrial chimeric RNA labeled withdigoxigenin (right panels). The cells lines are identified at the left.

FIG. 5A. In situ hybridization of several sections of human biopsiescorresponding to different tumor types. The tumor sections werehybridized with oligonucleotide probes complementary to the sensemitochondrial chimeric RNA, and labeled with digoxigenine (left panels).In addition, parallel tumor sections were hybridized witholigonucleotide probes complementary to the antisense mitochondrialchimeric RNA labeled with digoxigenin (right panels). FIG. 5B are insitu hybridization of different human tumors carried out witholigonucleotide probes complementary to the sense mitochondrial chimericRNA labeled with digoxigenin.

FIG. 6 In situ hybridization of normal proliferating cells. The sampleswere hybridized with probes targeted to the sense or the antisensemitochondrial chimeric RNA and labeled with digoxigenin. Stronghybridization signal was obtained with both probes, one complementary tothe sense mitochondrial chimeric RNA (left panels) as well as to theantisense mitochondrial chimeric RNA (right panels). The tissues orcells are identified at the left.

FIG. 7. Immunocytochemistry and in situ hybridization to show expressionchanges in human lymphocytes stimulated to proliferate with the mitogenPHA. After 48 h of stimulation with PHA, the lymphocytes express theantigens Ki-67 and PCNA (right panels). These antigens are not expressedin the control or resting lymphocytes (left panels). The in situhybridization was carried out with oligonucleotide probes targeted tothe sense and the antisense mitochondrial chimeric RNA and labeled withdigoxigenin. The stimulated lymphocytes over express the sense as wellas the antisense mitochondrial chimeric RNA (right panels).

FIG. 8 In situ hybridization of tumor cells showing localization of thesense mitochondrial chimeric RNA in the nucleolus. The cells or tumorsections are indicated at the left.

FIG. 9 Fluorescent microscopy to reveal changes occurring in tumoralHL-60 cells treated with oligonucleotides probes targeted to theantisense mitochondrial chimeric RNA. A, B, C and D show staining with acompound (VAD-fmok) that binds with high affinity to activated caspases.This compound is labeled with fluoresceine. The oligonucleotide probestargeted to the antisense mitochondrial chimeric RNA induce activationof caspases in similar manner than the drug staurosporin (compare B andC). Activated caspases are not detected in control untreated cells (A)or in cells treated with oligonucleotide probes targeted to the 12Smitochondrial RNA (D), as control. E and F show staining of HL-60 cellswith DAPI. The control cells (untreated) show homogeneous staining ofthe nucleus (E), while cells treated with the oligonucleotide probestargeted to the antisense mitochondrial chimeric RNA show massivefragmentation of the nucleus (F).

FIG. 10 Percent of apoptotic cells after different treatment conditionsof resting and proliferating lymphocytes. Apoptosis was measured inresting lymphocytes or PHA-stimulated lymphocytes by DAPI staining. Thebars 1 and 2 correspond to untreated cells. A low spontaneous apoptosisof control (1) or PHA-stimulated lymphocytes (2) was observed. A similarlow level of apoptosis was observed in resting lymphocytes (3) orPHA-stimulated lymphocytes (4) treated with 15 uM oligonucleotide probestargeted to the antisense mitochondrial chimeric RNA for 15 h, showingthat apoptosis is not induced in normal cells. As a control, restinglymphocytes and PHA-stimulated lymphocyte were treated withstaurosporine. Under these conditions, around 90% of resting lymphocytes(5) or PHA-stimulated lymphocytes (6) undergo apoptosis.

DETAILED DESCRIPTION OF THE INVENTION

The Human Mitochondrial Chimeric RNA Family

The present invention is based on the surprising discovery that humancells express a family of novel mitochondrial RNAs, referred to as thehuman mitochondrial chimeric RNAs.

One of these transcripts contains a long inverted repeat of 815nucleotides covalently joined to the 5′ end of the mitochondrial 16Sribosomal RNA, named sense mitochondrial chimeric RNA. The long invertedrepeat is fully complementary to the 16S ribosomal RNA from positions 51to 866, forming a long double stranded stem and a loop of 50nucleotides. As shown in FIG. 1A, the stem of 815 base pairs representsa significant problem for any reverse transcriptase to synthesize thecorresponding cDNA. Therefore a new strategy was used to amplify thisRNA by RT-PCR which is illustrated in FIG. 1A. After obtaining thesequence of each overlapping fragment, they were assembled as contigs toobtain the complete sequence of the sense mitochondrial chimeric RNAshown in SEQ ID NO 1 (FIG. 1A).

Other aspect of this invention is the discovery of other novel sensemitochondrial chimeric RNAs which are expressed in cells transformedwith the oncogenic human papilloma virus 16 or 18. Human foreskinkeratinocytes (HFK) where infected with HPV 16 or 18 (Hausen, Biochim.Biophys. Acta, 1288:F55-F78, 1996). The infection induces transformationor immortalization of the HFK. However, these cells are not tumorigenicsuch as the related SiHa cells (infected with HPV 16) or HeLa cells(infected with HPV 18). These cells express the sense mitochondrialchimeric RNA (SEQ ID NO 1) similar to SiHa and HeLa cells. However, thetransformed cells also express another second sense mitochondrialchimeric RNA which contains an inverted repeat of 754 nucleotides joinedto the 16S ribosomal RNA (FIG. 1B) (SEQ ID NO 2). This new sensemitochondrial chimeric RNA is down regulated or is not expressed innormal human cells (HFK) or in tumorigenic cells (SiHa or HeLa cells).

In another embodiment of this invention we determined the expression ofa third sense mitochondrial chimeric RNA in cells transformed withHTLV-1 (Kobayashi et al., EMBO J., 3:1339-1343, 1984). MT-2 cellsinfected with HTLV-1 express the sense mitochondrial chimeric RNA (SEQID NO 1) and the sense mitochondrial chimeric RNA expressed in cellstransformed with HPV 16 or 18 (SEQ ID NO 2). Besides these transcripts,the cell infected with HTLV-1 express a third sense mitochondrialchimeric RNA containing an inverted repeat of 694 nucleotides joined tothe 5′ end of the 16S ribosomal RNA. This novel RNA (FIG. 1C) (SEQ ID NO3) is not expressed in normal proliferating cells, in tumor cells or inHFK transformed with HPV 16 or 18.

Normal proliferating cells such as human foreskin keratinocytes (HFK) asdescribed in previous section also over express the sense mitochondrialchimeric RNA (FIG. 6) (SEQ ID NO 1). Human lymphocytes stimulated withmitogens such as phytohaemagglutinin (PHA) enter into the S phase of thecell cycle and begin the synthesis of DNA (Yu et al., J. Biol. Chem.,266:7588-7595, 1991). As proliferating cells, the lymphocytes alsoexpress antigens related to proliferation such as Ki-67 andproliferating cell nuclear antigen or PCNA (Bantis et al.,Cytopathology, 15:25-31, 2004). The stimulated lymphocytes also overexpress the sense mitochondrial chimeric RNA (SEQ ID NO 1). Otherproliferating cells such as lymphocytes in the germinal center of thespleen, spermatogonia, and embryonic cells also over express the sensemitochondrial chimeric RNA (SEQ ID NO 1) (FIG. 4). In contrast,non-proliferating cells such as non-stimulated lymphocytes, or musclecells do not express the sense mitochondrial chimeric RNA (FIG. 7).

In another embodiment of the invention, methods to differentiate anormal proliferating cells from a tumor cell are provided. As describedbefore, tumor and normal proliferating cells over express the sensemitochondrial chimeric RNA described in SEQ ID NO 1. In addition, inspecific situations of infection with HPV and HTLV-1, additionalchimeric RNA are found (SEQ ID NO 2 and SEQ ID NO 3). However, thepresent invention is also based on the surprising discovery that normalproliferating cells also over express an antisense mitochondrialchimeric RNA. The expression of the antisense mitochondrial chimeric RNAwas confirmed in human lymphocytes stimulated with PHA (FIG. 7), innormal HFK and in other normal proliferating cells (FIG. 6). Anothersurprising discovery of the present invention is that different tonormal proliferating cells, tumor cells do not express the antisensemitochondrial chimeric RNA or markedly down regulated the production(compare FIG. 4 with FIG. 6 and FIG. 7).

Using the same strategy to amplify by RT-PCR the chimeric RNA based inoverlapping fragments described earlier, the structure of the antisensemitochondrial chimeric RNA was determined (FIG. 3). The sequencing andassembling in contigs reveals a complex family of antisensemitochondrial chimeric RNAs containing inverted repeat of differentlengths joined to the 5′ end of the antisense 16S mitochondrialribosomal RNA (FIGS. 3A, B and C) (SEQ ID NO 4, SEQ ID NO 5, SEQ ID NO6). The sequence also reveals the formation of double strandedstructures or stems in these RNA and the formation of loops with 17, 96and 451 nucleotides, respectively (FIGS. 3A, B and C, SEQ ID NO 4, SEQID NO 5, SEQ ID NO 6).

In other embodiment of the invention, methods and compositions areprovided to follow the oncogenic transformation of cells by an oncogenicvirus. HeLa cells (infected with HPV 18) or SiHa cells (infected withHPV 16) over express the sense mitochondrial chimeric RNA but downregulate the expression of the antisense mitochondrial chimeric RNAs. Onthe other hand, HFK as normal proliferating cells, over express both thesense as well as the antisense mitochondrial chimeric RNAs. Aftertransformation of HFK with HPV 16 or HPV 18, the cells acquire the tumorphenotype: they over express the sense mitochondrial chimeric RNA anddown regulate the expression of the antisense mitochondrial chimericRNA. The over expression of the sense mitochondrial chimeric RNA anddown regulation of the antisense mitochondrial chimeric RNA can bedetermined by in situ hybridization, amplification of the RNA by RT-PCRor by using other methods to determine a RNA by ways well known to theperson skilled in the art. These methods and compositions can be usedalso to determine the change in the expression of the chimeric RNAfamily in cells transformed with other oncogenic virus or by compoundsthat induce transformations or carcinogenesis (McKinnell et al., “Thebiological basis of Cancer, Cambridge University Press 1998).

Cancer and Pre-Cancer Diagnostics.

According to the present invention methods and compositions are providedto detect in a biological sample the presence of the sense mitochondrialchimeric RNAs and the antisense mitochondrial chimeric RNAs. In onepreferred embodiment, the detection is carried out by in situhybridization. The detection of the sense mitochondrial chimeric RNA andthe antisense mitochondrial chimeric RNAs in the cells of the biologicalsample indicates that the cells are normal proliferating cells. Inanother embodiment, the result of the in situ hybridization with tumorcells will show expression of the sense mitochondrial chimeric RNA anddown regulation or absence of the antisense mitochondrial chimeric RNA.If the biological sample contains non-proliferating normal cells the insitu hybridization will show that neither the sense mitochondrialchimeric RNA nor the antisense mitochondrial chimeric RNA are expressed.

Biological samples are understood as normal cells (resting orproliferating cells) in culture or in blood smears or bone marrowsmears, tumor cells in culture and normal cells transformed withoncogenic virus. Additionaly, biological samples comprise cells obtainedfrom the urine or the bladder washing from patients suspecting of havingbladder or kidney cancer, or cells from saliva in patients suspecting ofhaving head and neck cancers, or cells from bronchoalveolar lavage frompatients suspecting of having lung cancer. Also, biological samplescomprise cells smears from the blood of patients suspecting of havingleukemia or cell smears from blood or lymph, lymph node of patientssuspecting of having metastasis.

The biological samples according to the invention include the use ofrapidly frozen tissue or cells samples for histopathological analysis,art well know by artisans in the field. Alternatively, the biologicalsample can be biopsies of sections fixed by using chemical treatmentthat can be accomplished by the wide variety of fixation protocols knownin the art (Frederick et al, Current Protocols In Molecular Biology,Volume 2, Unit 14, Frederick M. Ausubul et al. edS., 1995; Celis, CellBiology, A Laboratory Handbook, Julio E. Celis, ed., 1994). Thebiological samples can also be non-fixed biological materials that arenot been chemically modified or treated with formalin or other fixativewell known in the art.

Alternatively, the in situ hybridization can be carried out by usingbiological samples embedded in materials such as paraffin or otherembedding polymers. The blocks obtained after embedding can be sectionedwith a microtome in section of about 4 to about 10 μm of thickness. Thesection can then be applied to glass or plastic slides coated with anadhesive substance know in the art such as polylysine or mussel adhesiveprotein (Burzio et al., Curr. Opin. Biotechnol., 8:309-312, 1997).

The in situ hybridization of the present invention can be carried out inways well known to persons skilled in the art. For example, ahybridization solution comprising one or more labeled probes targeted toone or more of the sequences of sense mitochondrial chimeric RNA (SEQ IDNO 1, SEQ ID NO 2, SEQ ID NO 3) or antisense mitochondrial chimeric RNA(SEQ ID NO 4, SEQ ID NO 5, SEQ ID NO 6) within the cell, is contactedwith the cell under hybridization conditions. The hybridization signalis then compared with a predetermined hybridization pattern from normalor control cancer and pre-cancer cells.

As used herein, the labeled probes to carry out the in situhybridization are RNA, DNA or synthetic nucleic acids that can beprepared by any method known in the art. Synthetic nucleic acids includeriboprobes transcribed in vitro or PCR fragments. In a preferredembodiment of this invention, synthetic complementary oligonucleotidescan be used. The complementary oligonucleotide probes are at least about10 nucleotides in length, most preferably at least about 14, and mostpreferably at least 18 nucleotides in length. The skilled artisanunderstand that the length can extend from 10 nucleotides or more to anylength which still allows hybridization to the sense mitochondrialchimeric RNAs or the antisense mitochondrial chimeric RNAs. In apreferred embodiment herein, the length is about 30 nucleotides, morepreferably about 25 nucleotides, and most preferably between 10 to 50nucleotides in length. Longer probing nucleic acids may also be used.The sequences of the probe is at least ninety five percent homologous tothe sequences listed in SEQ ID NO 1, SEQ ID NO 2, SEQ ID NO 3, SEQ ID NO4, SEQ ID NO 5 and SEQ ID NO 6.

The complementary oligonucleotide probes of the present invention willgenerally contain phosphodiester bonds, although in some cases,oligonucleotides probe analogs are included that may have alternateinter nucleoside linkages, comprising, but not limited to,phosphorothioate (Mag et al., Nucleic Acids Res. 19:1437-1441, 1991; andU.S. Pat. No. 5,644,048), peptide nucleic acid or PNA (Egholm, Nature,365:566-568, 1993; and U.S. Pat. No. 6,656,687), phosphoramide(Beaucage, Methods Mol. Biol. 20:33-61, 1993), phosphorodithioate(Capaldi et al., Nucleic Acids Res., 28:E40, 2000). Other complementaryoligonucleotides analogs include such as, but not limited to, morpholino(Summerton, Biochim. Biophys. Acta, 1489:141-158, 1999), lockedoligonucleotides (Wahlestedt wt al., Proc. Natl. Acad. Sci. US,97:5633-5638, 2000), peptidic nucleic acids or PNA (Nielsen et al.,1993; Hyrup and Nielsen, 1996) or 2-o-(2-methoxy) ethyl modified 5′ and3′ end oligonucleotides (McKay et al., J. Biol. Chem., 274:1715-1722,1999). All of these references are hereby expressly incorporated byreference. The nucleic acid may contain any combination of deoxyribo-and ribo-nucleotides, and any combination of bases, including uracil,adenine, thymine, cytosine, guanine, inosine, xathanine hypoxathanine,isocytosine, isoguanine, etc.

In another embodiment of the invention, the nucleic acid oroligonucleotide probes have to be labeled to detect the hybridizationwith the sense mitochondrial chimeric RNAs or the antisensemitochondrial chimeric RNAs. The probes may be labeled with a detectablemarker by any method known in the art. Methods for labelling probesinclude random priming, end labeling, PCR and nick translation.Enzymatic labeling is conducted in the presence of nucleic acidpolymerase, three unlabeled nucleotides, and a fourth nucleotide whichis either directly labeled, contains a linker arm for attaching a label,or is attached to a hapten or other molecule to which a labeled bindingmolecule may bind. Suitable direct labels include radioactive labelssuch as .sup.32 P, .sup.3H, and .sup.35 S and non-radioactive labelssuch as fluorescent markers. Preferred fluorochromes (fluorophores)include 5(6)-carboxyfluorescein,6-((7-amino-4-methylcoumarin.-3-acetyl)amino)hexanoic acid, 5(and6)-carboxy-X-rhodamine, Cyanine 2 (Cy2) Dye, Cyanine 3 (Cy3) Dye,Cyanine 3.5 (Cy3.5) Dye, Cyanine 5 (Cy5) Dye, Cyanine 5.5 (Cy5.5) DyeCyanine 7 (Cy7) Dye, Cyanine 9 (Cy9) Dye (Cyanine dyes 2, 3, 3.5, 5 and5.5 are available as NHS esters from Amersham, Arlington Heights, Ill.)or the Alexa dyes comprising Alexa 488, Alexa 532, Alexa 556, Alexa 590,etc. (Molecular Probes, Eugene, Oreg.).

Probes may be indirectly labeled by incorporating a nucleotidecovalently linked to a hapten or other molecule. Preferred haptens, butnot limited to, include 5(6)-carboxyfluorescein, 2,4-dinitrophenyl,digoxigenin and biotin, and performing the detection of the probe with alabeled antibody directed to that hapten or other molecule. In the caseof biotin, detection can be carry out with avidin or streptavidinconjugated to a detectable label. Antibodies, streptavidin and avidinmay be conjugated with a fluorescent marker, or with an enzymatic markersuch as alkaline phosphatase or horseradish peroxidase to render themdetectable. Conjugated streptavidin, avidin and antibodiesanti-digoxigenin are commercially available from companies such asVector Laboratories (Burlingame, Calif.) and Boehringer Mannheim(Indianapolis, Ind.). In another embodiment, the antibodies orstreptavidin can be conjugated to quantum dot with superior and morestable fluorescence emission (Wu et al., Nature Biotechnol. 21:41-46,2003).

The enzyme in the conjugated of antibodies and streptavidin can bedetected through a calorimetric reaction by providing a substrate forthe enzyme. In the presence of various substrates, different colors areproduced by the reaction, and these colors can be visualized toseparately detect multiple probes. Any substrate known in the art may beused. Preferred substrates for alkaline phosphatase include5-bromo-4-chloro-3-indolylphosphate (BCIP) and nitro blue tetrazolium(NBT). The preferred substrate for horseradish peroxidase isdiaminobenzoate (DAB). Those skilled in the art understand that otherenzymatic activities also con be used.

In another embodiment of the present invention, the conditions to carryout in situ hybridization to achieve accurate and reproducible resultsare described. Those of ordinary skill in the art of nucleic acidhybridization will recognize that factors commonly used to control thestringency of hybridization include formamide concentration or otherchemical denaturant reagent, salt concentration or variable ionicstrength, hybridization temperature, detergent concentration, pH and thepresence or absence of chaotropic agents. These stringency factors canbe modulated to thereby control the stringency of hybridization of theoligonucleotide probes for the chimeric RNA. Optimal stringency for anassay may be experimentally determined by examination of each stringencyfactor until the desired degree of discrimination is achieved.

Other conditions that have to be controlled for optimal in situhybridization are for example the use of chemical agent to blocknon-specific binding of the probe to components present in thebiological samples others than the target chimeric RNAs. The blockingagent, but not limited to, are RNA, DNA or oligonucleotides without alabel. The blocking agent incorporated in the hybridization solutionwill suppress the non-specific binding of the labeled probe, and hence,increase the signal to noise ratio of the assay. In yet another aspectof the invention, the probe has a sequence complementary to the sequenceof the sense or antisense mitochondrial chimeric RNAs (see SEQ ID NO 1,SEQ ID NO 2, SEQ ID NO 3, SEQ ID NO 4, SEQ ID NO 5 and SEQ ID NO 6).

Fixation of the biological sequence is also an important aspect of insitu hybridization that has to be determined experimentally. Highlycross-linking fixative such as glutaraldehide is not recommended sinceit may block the access of the probe to the target sense mitochondrialchimeric RNA or antisense mitochondrial chimeric RNA. The preferredmethod of this invention is to fix the biological sample with formalin,although frozen samples are also preferred. To expose the sensemitochondrial chimeric RNAs or the antisense mitochondrial chimeric RNAto the labeled probe, additional procedures can be used. For example,the biological sample can be digested with proteinase K to removeproteins that can block the access of the probe to the target chimericRNAs. Treatment of biological samples with proteinase K or otherproteases previous to in situ hybridization are well known for thoseartisans in the art.

As described before, the presence of long inverted repeats in thechimeric RNA and in the antisense chimeric RNAs, induce the formation ofhighly stable double stranded structures. These structures together withthe secondary structures of the single strand region of the chimericRNAs may constitute barriers for the access of the probe to the targetchimeric RNAs. Therefore, in another aspect of the invention, thebiological sample is treated with 0.2 M HCl for 10 min at roomtemperature to denature the chimeric RNA. Then the sample is rapidlyneutralized by several washes with a buffer solution at pH 7.4 beforeapplying the in situ hybridization protocol described herein. Aided byno more than routine experimentation and the disclosure provided herein,those of skilled in the art will easily be able to determine suitablehybridization conditions for performing assays utilizing the methods andcompositions described herein. Suitable in-situ hybridization conditionsare those conditions suitable for performing an in-situ hybridizationprocedure. Thus, suitable in-situ hybridization conditions will becomeapparent using the disclosure and references herein; with or withoutadditional routine experimentation.

In another embodiment of the present invention, the localization of thesense mitochondrial chimeric RNAs as determined by in situ hybridizationmay have important information for prognosis and management of thepatient with cancer. In tumor cells, the sense mitochondrial chimericRNA is found mostly in the cytoplasm in close association with lateendosomes/lysosomes. However, localization in the nucleolus is alsofound in certain cells. In tumor cells present in human biopsies, thehybridization signal reveals that the sense mitochondrial chimeric RNAis in the cytoplasm only, or in the cytoplasm and the nucleolus or inthe cytoplasm and the nucleus. Therefore the different localizations mayhave an important prognostic value. In a preferred embodiment, panel ofhuman biopsies, for example from breast, colorectal or prostate tumors,may be studied by in situ hybridization to detect the chimeric RNA.Together with the positive hybridization signal (independent on how theprobe was labeled), the intracellular localization (only cytoplasm,cytoplasm and nucleus or cytoplasm and nucleolus) should be establishedin each tumor and the results compared with the survival of eachpatient.

In another aspect of this invention, mixture of individual cellscontaining normal and/or tumor cells can be subjected to hybridizationin suspension with oligonucleotide probes labeled with fluorochomes andcomplementary to the sense mitochondrial chimeric RNA and to theantisense mitochondrial chimeric RNA. For example the probe or probestargeted to the sense mitochondrial chimeric RNA can be labeled withrhodamin, and the probe or probes targeted to the antisensemitochondrial chimeric RNA can be labeled with Alexa 488. Afterhybridization and washing under the conditions described before, thecells can be analyzed by intracellular labeling flow cytometry.

The preferred embodiment of the invention is to use in situhybridization since the information obtained about the specificlocalization of the chimeric RNA in the tumor cell provides importantadditional information of prognosis.

In yet another embodiment of the invention, alternative molecularmethods can be used to detect the expression of the chimeric RNA anddifferential expression of the sense and antisense chimeric RNA innormal, pre-cancer and cancer cells. These alternative methods include,but are not limited to, Northern blot, dot blot, oligonucleotide arraysfor the chimeric RNA and the antisense chimeric RNAs, amplification ofthe RNA by RT-PCR, amplification of the RNA by in vitro transcriptionmediated amplification or TMA, S1 or ribonuclease protection assays,etc.

In one embodiment of the present invention, the sense mitochondrialchimeric RNA can be detected for diagnostic purposes with a probeobtained by amplification of a region that contains part of the 5′ endof the 16S ribosomal RNA and a partial or full region of the invertedrepeat. As shown in FIG. 1, the reverse primer can be for example primer1 (SEQ ID NO 139), and the forward primers can be primers 3, 4, 5, 6 or7 (SEQ ID NOS 129, 116, 106, 102, 63). Primers located at otherpositions can also be used and they are easily designed by those skilledin the art. In another aspect of this invention, the cDNA which can besynthesized with an enzyme with reverse transcription activity andrandom primers such as hexamers or longer, familiar to those skilled inthe art.

The amplicons of 210, 350, 500 or 850 bp obtained, or of other sizesresulting by using primers located at other positions, can be detectedby gel electrophoresis in agarose gel or polyacrylamide gels (Sambrooket al., 1989) and staining with ethidium bromide or other intercalatingdyes. The amplicons can be purified according to the manufacturersinstructive.

The detection of the mitochondrial chimeric RNA can be carried out byNorthern blot analysis (Sambrook et al., 1989). After separation of theRNAs in an agarose gel, the fragments are transferred to a membrane(nitrocellulose or Nylon) by procedures well known to those skilled inthe art (Sambrook et al., 1989). To probe the membranes, a fragment of250 bp corresponding to position 1000 to 125 of the sense mitochondrialchimeric RNA can be amplified. The amplicon is purified (Wizard,Promega) according to the manufactere's intraction, and 10 nanograms areused as template for a second amplification. This amplification iscarried out with the standard mixture of PCR (Invitrogen) plus 5 microCurie of ³²P-α-dCTP (Amerscham). The radioactive amplification fragmentis denatured by incubation at 95° C. for 10 minutes and the denaturedprobe was added to the hybridization mixture. The membranes arehybridized for 16 hours at 65° C. and then washed twice with 2 times SSCbuffer, twice with 0.5 SSC at 60° C. and 0.2 SSC at 45° C. (Sambrook etal., 1989). The washed membrane was exposed to X-ray film overnight at−70° C. (Sambrook et al., 1989). The hybridization signal on themembrane corresponds to a major component of about 2,400 nucleotideswhich is the size corresponding to the 16S ribosomal RNA (1559nucleotides) plus the inverted repeat of 815 nucleotides.

In another embodiment of the invention, part of the sense mitochondrialchimeric RNA can be detected after ribonuclease digestion of total RNAextracted from cells or tissues. The double stranded structure or thestem of the sense mitochondrial chimeric RNA is resistant to digestionwith ribonuclease A. Total RNA from cells or tissues extracted withTriZol (Invitrogen) is dissolved in a small volume of 2 times SSC. Thesolution is incubated with ribonuclease A (Sigma) at a finalconcentration of 50 micrograms per ml. After 30 min at 25° C., the RNAresistant to the nuclease is extracted with TriZol and precipitated withisopropanol at −20° C. overnight. The RNA resistant to the nuclease isdissolved in distilled DEPC-treated water and used as template forRT-PCR amplification. This amplification, carried out with primerstargeted to positions 55 and 790 of the 16S ribosomal RNA, yields afragment of about 730 base pairs with a sequence that shows 100%identity with the sequence of the stem of the sense mitochondrialchimeric RNA (SEQ ID NO 1). In contrast, the single strand of thechimeric RNA and corresponding to the 3′ half, or the 12S mitochondrialribosomal RNA, or the 18S ribosomal RNA or the mRNA for GAPDH aretotally digested by the treatment with the ribonuclease A, andtherefore, no amplification product is obtained when primers targeted tothese RNAs are used.

In another aspect of the invention, the stem of the sense mitochondrialchimeric RNA obtained after treatment of total RNA with ribonuclease Acan be detected by Northern blot. The RNA resistant to the nuclease andrecovered by extraction with TriZol and precipitation with isopropanol,is separated by electrophoresis in an agarose gel. After transfer, themembrane is blotted with the probe described before and used forNorthern blot (Sambrook et al., 1989) for the sense mitochondrialchimeric RNA.

In yet another embodiment, this invention is directed to kits suitablefor performing an assay which detect the sense mitochondrial chimericRNAs or the antisense mitochondrial chimeric RNA in biological samples.The general and the preferred embodiment, compositions and methods areprovided which are suitable for the detection of the chimeric RNA andthe antisense chimeric RNA by in situ hybridization have been previouslydescribed herein. Preferred oligonucleotide probes sequences, but notlimited-to, are listed. Furthermore, methods suitable for usingoligonucleotide probes or set of oligonucleotide probes of a kit todetect the chimeric RNAs or the antisense chimeric RNAs in a sample havebeen previously described herein.

The kit of this invention comprises one or more oligonucleotide probesand other reagents or compositions which are selected to perform in situhybridization used to detect the sense mitochondrial chimeric RNAs orthe antisense mitochondrial chimeric RNAs in a sample. Each set of twoor more oligonucleotide probes are preferably labeled with independentdetectable moieties so that in an individual cell of the biologicalsample the sense mitochondrial chimeric RNAs or the antisensemitochondrial chimeric RNAs can be detected. In a preferred embodiment,the oligonucleotide probes of the kit which are use to detect the sensemitochondrial chimeric RNAs or the antisense mitochondrial chimeric RNAsare each set labeled with a different hapten. The hapten can be biotin,digoxigenin or fluoresceine that can be recognized in the method of insitu hybridization with antibodies or streptavidin labeled withdifferent enzymes (e.g. alkaline phosphatase or peroxidase).Alternatively, each oligonucleotide probe of each set of probes can belabeled with independent detectable fluorescent groups. For example, theset of oligonucleotides probes to detect the sense mitochondrialchimeric RNA can be labeled with rhodamin, while the set ofoligonucleotides probes to detect the antisense mitochondrial chimericRNAs can be labeled with Alexa 488. Furthermore, methods are provided todetermine the localization of the chimeric RNA or the antisense chimericRNAs in cells of the biological sample. Additionally, compositions andmethods of the invention can be used to determine the co-localization ofthe chimeric RNAs or the antisense chimeric RNAs with specific markersof the different cell organelles, by using confocal microscopy analysis.

The compositions and methods provided herein are deemed particularlyuseful for the detection and diagnostic of pre-cancer and cancer. Theterm cancer as provided herein, includes cells afflicted by any one ofthe following identified anomalous conditions. These include myeloidleukemia acute or chronic, lymphoblastic leukemia acute or chronic,multiple myeloma, Hodgkin's disease, non-Hodgkin's lymphoma or malignantlymphoma; stomach carcinoma, esophagus carcinoma or adenocarcinoma,pancreas ductal adenocarcinoma, insulinoma, glucagonoma, gastrinoma,small bowel adenocarcinoma, colorectal carcinomas; hepatocellularcarcinoma, hepatocellular adenoma; carcinoids, genitourinary tract suchas kidney adenocarcinoma, Wilm's tumor, bladder and urethra carcinomaand prostate adenocarcinoma, testis cancer like seminoma, teratoma,teratocarcinoma, interstitial cell carcinoma; uterus endometrialcarcinoma, cervical carcinoma, ovarian carcinoma, vulva and vaginacarcinoma, Sertoli-L-eydig cell tumors, melanoma, and fallopian tubescarcinoma; lung, alveolar and bronchiolar carcinomas; brain tumors; skinmalignant melanoma, basal cell carcinoma, squamous cell carcinoma andKarposi's sarcoma. Also fibrosarcoma, angiosarcoma and rhabdomyosarcomaof the heart and other malignancies that are familiar to those skilledin the art.

Cancer and Pre-Cancer Therapy

Chemotherapeutic drugs can induce a series of cellular responses thatimpact on tumor cell proliferation and survival. The best studied ofthese cellular responses is apoptosis and is evident at the present timethat anti-cancer drugs can kill tumor cells by activating commonapoptotic pathways. Unfortunately, these drugs also affect rapidlydividing normal cells of the bone marrow, normal hematopoietic andintestinal cells and hair matrix keratinocytes (McKinnell et al., Thebiological Basis of cancer, 1998; Komarov et al., Science 285:1733-1737,1999; Johnstone et al., Cell 108:153-164, 2002).

On the other hand, many tumor cells have mutated apoptotic initiatorfactors, regulatory factors and executioner factors of apoptosis, whichexplain why tumor cell of different cancer types become resistant to avariety of chemotherapeutic drugs and radiation. Mutations have beenreported of factors of the intrinsic pathway, post mitochondrial eventsand extrinsic pathway of apoptosis (Rampino et al., Science 275:967-969,1997; Vogelstein et al., Nature 408: 307-310, 2000; Teitz et al., NatureMed. 6:529-535, 2000; Reed, J. Clin. Oncol., 17:2941-2953, 1999;Johnston et al., Cell 108:153-164, 2002). Therefore, a paradigm of acancer therapy treatment is a procedure that selectively triggersapoptosis of tumor cells, that does not alter normal proliferating cellsand that bypasses the altered or mutated factors of the differentapoptotic pathways.

The compositions and methods of the present invention, are based on thediscovery that tumor and pre-tumor cells over express the sensemitochondrial chimeric RNA at similar levels of the normal proliferatingcells. However, and in contrast with normal proliferating cells, tumorand pre-tumor cells down regulate the expression of the antisensemitochondrial chimeric RNA.

The structures of these transcripts are shown in FIG. 1 and FIG. 3, andthe corresponding sequences in SEQ ID NO 1, SEQ ID NO 2, SEQ ID NO 3,SEQ ID NO 4, SEQ ID NO 5 and SEQ ID NO 6.

In contrast, and constituting another surprising discovery, pre-tumorand tumor cells overexpress the sense mitochondrial chimeric RNA anddown regulate the expression of the antisense mitochondrial chimericRNA. The suppression or inhibition of the synthesis of the antisensemitochondrial chimeric RNA in pre-tumor and tumor cells constitutes anovel difference on phenotype between a cancer cell and a normalproliferating cell, which is considered as one of the major embodimentsof the present invention. Moreover, tumor cells in human biopsies ofdifferent cancer types, also exhibit the same phenotype of cancer cellsin culture (FIGS. 5A and 5B).

Although the function of the sense mitochondrial chimeric RNA and theantisense mitochondrial chimeric RNA is not clear, a close correlationexist between the expression of these RNAs and cell proliferation. Forexample, normal proliferating cells in tissues like liver, kidney andspleen, and defined as such by the expression of the antigens suchKi-67, PCNA or phosphorylated histone H3, over express the sensemitochondrial chimeric RNA as well as the antisense mitochondrialchimeric RNA. In the non-proliferating cells of the same tissues, whichdo not express Ki-67 or PCNA, the sense mitochondrial chimeric RNA andthe antisense mitochondrial chimeric RNA are not expressed. Furthermore,and as illustrated in FIG. 7, human lymphocytes stimulated with themitogen PHA synthesize DNA and express the proliferating antigens Ki-67and PCNA. The stimulated lymphocytes also over express the sensemitochondrial chimeric RNA as well as the antisense mitochondrialchimeric RNA (FIG. 7). In contrast, resting lymphocytes ornon-stimulated lymphocytes do not express neither the sensemitochondrial chimeric RNA nor the antisense mitochondrial chimeric RNA.

The previous finding, which is one fundamental part of the presentinvention, shows that while normal proliferating cells express the senseand antisense mitochondrial chimeric RNAs, tumor cells express the sensemitochondrial chimeric RNA and down regulate the expression of theantisense mitochondrial chimeric RNA. To understand the function ofthese RNAs in cell proliferation, cancer cells in culture were treatedwith antisense oligonucleotides targeted to the sense mitochondrialchimeric RNAs (SEQ ID NO 1, SEQ ID NO 2, SEQ ID NO 3) or to theantisense mitochondrial chimeric RNA (SEQ ID NO 4, SEQ ID NO 5, SEQ IDNO 6). The results, constituting another surprising discovery, showedthat under these conditions the cells undergo programmed cell death orapoptosis. After treatment with the oligonucleotides complementary tothe sense or antisense mitochondrial chimeric RNAs for 6 to 15 hours,between 75 to 96% of the cells undergo apoptosis (Table 2). The changeobserved in the treated cells were chromatin condensation, nuclearfragmentation, DNA fragmentation, activation of caspases and alteredprocess of the cell membrane. Control oligonucleotides with 4 o moremismatches or scrambled oligonucleotides did not induce apoptosis. Also,cells were not affected if treated with oligonucleotides targeted to thesense or antisense 12S mitochondrial RNA or targeted to the mRNA or theantisense transcript of the mitochondrial ND1 subunit. In general,oligonucleotides targeted to the antisense mitochondrial chimeric RNAwere much more effective, at the same concentration, thanoligonucleotides targeted to the sense mitochondrial chimeric RNA. Thiswas an expected result since the tumor cells over express the sensemitochondrial chimeric RNA and therefore is more difficult to reach aconcentration of oligonucleotides inside the cell to interfere with allthe copies of this transcript. On the other hand, since tumor cells downregulate the antisense mitochondrial chimeric RNA, it should be easierto interfere with this RNA since there is a lower number of copies percells.

The induction of apoptosis is also selective for tumor cells. Restinghuman lymphocytes or human lymphocytes stimulated for 48 hours with PHAare not affected by the treatment with oligonucleotides complementary tothe antisense mitochondrial chimeric RNAs or targeted to the sensemitochondrial chimeric RNA even after overnight treatment and with ahigh dose of complementary oligonucleotides (15 uM).

Apoptosis induction by treatment with complementary oligonucleotidestargeted to the antisense mitochondrial chimeric RNA (SEQ ID NO 4, SEQID NO 5, SEQ ID NO 6) has been achieved, but not limited to,promielocytic leukemia cell HL-60, acute lymphoblastic leukemia MOLT-4,a T-lymphocitic leukemia cells, Jurkat, a T-cell leukemia, Devernelle orB-lymphoma, NSO/2 or myeloma, HeLa cells, DU145, PC-3, Caco-2, Hep-2 andHepG2. Two cells, MCF/7 (breast carcinoma) and melanoma, that can beconsidered as paradigm of treatment-resistant (chemotherapy orradiotherapy) tumor cells undergo apoptosis over 80% when treated for 15hours with complementary oligonucleotides targeted to the antisensemitochondrial chimeric RNA (SEQ ID NO 4, SEQ ID NO 5, SEQ ID NO 6). Alower apoptotic effect was obtained with oligonucleotides complementaryto the sense chimeric RNA (SEQ ID NO 1). As reported before,oligonucleotides with 4 mismatches or scrambled oligonucleotides do notinduce cell death.

Described below are methods and compositions for treating cancer usingthe sense chimeric RNAs and the antisense chimeric RNAs as a therapeutictarget. The preferred embodiment, but not limited to, are methods andcompositions for treating cancer using oligonucleotides complementary tothe antisense chimeric RNAs. The outcome of this treatment is to atleast produce in a treated subject a healthful benefit, which in thecase of cancer, includes but is not limited to remission of the cancer,palliation of the symptoms of the cancer, and control of metastaticspread of the cancer. All such methods involve the induction ofapoptosis in the tumor cells and with minor effect in normal cells.Complementary oligonucleotides that target specific RNAs have been usedto diminish or abrogate the expression of a large variety of mRNA or thesynthesis of the corresponding proteins (e.g. Vickers et al., J. Biol.Chem., 278:7108-7118, 2003). At present, about 42 antisenseoligonucleotides with different chemistries are currently being screenedas potential drugs (Stephens and Rivers, Curr. Opin. Mol. Therapeut.,5:118-122, 2003) (see also as examples U.S. Pat. Nos. 5,801,154;6,576,759; 6,720,413; 6,573,050 and 6,673,917). All of these referencesare hereby expressly incorporated by reference.

In one aspect of this invention, one or more oligonucleotides targetedto the antisense mitochondrial chimeric RNA can be used. The use of twoor more complementary oligonucleotides is more effective and shows somedegree of synergism.

The oligonucleotide of the invention may be complementary to theantisense mitochondrial chimeric RNA or to the sense mitochondrialchimeric RNA. The complementary oligonucleotides will bind to theantisense mitochondrial chimeric RNAs or to the sense mitochondrialchimeric RNAs and interfere with their functions. Absolutecomplementarity, although preferred, is not required. An oligonucleotidesequence “complementary” to a portion of an RNA, as referred to herein,means a sequence having sufficient complementarity to be able tohybridize with the RNA, forming a stable duplex. The ability tohybridize will depend on both the degree of complementarity and thelength of the oligonucleotide. Generally, the longer the hybridizingnucleic acid, the more base mismatches with an RNA it may contain andstill form a stable duplex. Those skilled in the art can ascertain atolerable degree of mismatch by use of standard procedures to determinethe melting point of the hybridized complex.

In general, complementary oligonucleotides to hybridize with mRNAs fordifferent proteins are targeted to the 5′ untranslated region of themRNA including the complement of the AUG start codon, or the 3′untranslated region to be more effective. Oligonucleotides complementaryto mRNA coding regions are less efficient inhibitors of translation (seeprevious references). The sense mitochondrial chimeric RNA and theantisense mitochondrial chimeric RNA are non-coding RNA and thereforethe target region of the oligonucleotides can be complementary to anyregion of these transcripts. The most effective regions are locatedaround the single-stranded segments of the antisense mitochondrialchimeric RNA determined by scanning the sequences of the antisense orthe sense mitochondrial chimeric RNA with complementary oligonucleotidesdesigned every 30 nucleotides. Those skilled in the art will understandthat other sequences within the complete sequences of the transcripts ofSEQ ID NO 1, SEQ ID NO 2, SEQ ID NO 3, SEQ ID NO 4, SEQ ID NO 5, and SEQID NO 6, are targets to design alternative complementaryoligonucleotides.

The complementary oligonucleotides targeted to the antisensemitochondrial chimeric RNA or to the sense mitochondrial chimeric RNAresulting in the induction of tumor cell death according to the presentinvention will generally contain backbones different to the naturalphosphodiester bonds. The oligonucleotides can have alternate internucleoside linkages, comprising, but not limited to, phosphorothioate(Mag et al., Nucleic Acids Res. 19:1437-1441, 1991; and U.S. Pat. No.5,644,048), peptide nucleic acid or PNA (Egholm, Nature, 365:566-568,1993; and U.S. Pat. No. 6,656,687), phosphoramide (Beaucage, MethodsMol. Biol. 20:33-61, 1993), phosphorodithioate (Capaldi et al., NucleicAcids Res., 28:E40, 2000). Other oligonucleotide analogs include suchas, but not limited to, morpholino (Summerton, Biochim. Biophys. Acta,1489:141-158, 1999), locked oligonucleotides (Wahlestedt wt al., Proc.Natl. Acad. Sci. US, 97:5633-5638, 2000), peptidic nucleic acids or PNA(Nielsen et al., 1993; Hyrup and Nielsen, 1996) or 2-o-(2-methoxy) ethylmodified 5′ and 3′ end oligonucleotides (McKay et al., J. Biol. Chem.,274:1715-1722, 1999). All of these references are hereby expresslyincorporated by reference. The nucleic acids may contain any combinationof deoxyribo- and ribo-nucleotides, and any combination of bases,including uracil, adenine, thymine, cytosine, guanine, inosine,xathanine hypoxathanine, isocytosine, isoguanine, etc.

The complementary oligonucleotides according to the invention maycomprise at least one modified base moiety which is selected from thegroup including but not limited to 5-fluorouracil, 5-bromouracil,5-chlorouracil, 5-iodouracil, hypoxanthine, xanthine, 4-acetylcytosine,5-(carboxyhydroxylmethyl) uracil,5-carboxymethylaminomethyl-2-thiouridine,5-carboxymethylaminomethyluracil, dihydrouracil,beta-D-galactosylqueosine, inosine, N6-isopentenyladenine,1-methylguanine, 1-methylinosine, 2,2-dimethylguanine, 2-methyladenine,2-methylguanine, 3-methylcytosine, 5-methylcytosine, N6-adenine,7-methylguanine, 5-methylaminomethyluracil,5-methoxyaminomethyl-2-thiouracil, beta-D-mannosylqueosine,5′-methoxycarboxymethyluracil, 5-methoxyuracil,2-methylthio-N6-isopentenyladenine, uracil-5-oxyacetic acid (v),wybutoxosine, pseudouracil, queosine, 2-thiocytosine,5-methyl-2-thiouracil, 2-thiouracil, 4-thiouracil, 5-methyluracil,uracil-5-oxyacetic acid methylester, uracil-5-oxyacetic acid (v),5-methyl-2-thiouracil, 3-(3-amino-3-N-2-carboxypropyl) uracil, (acp3)w,and 2,6-diaminopurine

The complementary oligonucleotides may also comprise at least onemodified sugar moiety selected from the group including but not limitedto arabinose, 2-fluoroarabinose, xylulose, and hexose.

In another embodiment of the present invention, the complementaryoligonucleotides are designed to hybridize with any region of theantisense mitochondrial chimeric RNA or to any region of the sensemitochondrial chimeric RNA. The complementary oligonucleotides should beat least ten nucleotides in length, and are preferably complementaryoligonucleotides ranging from 10 to about 50 nucleotides in length. Inspecific aspects, the complementary oligonucleotide is at least 12nucleotides, at least 18 nucleotides, at least 22 nucleotides, at least30 nucleotides, at least 50 nucleotides.

It is important to consider for in vitro as well as for in vivoexperiments to utilize controls that distinguish between antisenseinterference with the function of the antisense mitochondrial chimericRNA or the sense mitochondrial chimeric RNA with nonspecific biologicaleffects of antisense or complementary oligonucleotides. Therefore, thedesign of the oligonucleotides has to avoid the presence in the sequenceof CpG tracks, 5′ GGGG tracks and other sequences that have toxic effectin animal cells as reported in U.S. Pat. No. 6,673,917, incorporatedherein by reference. Also the presence of the sequence 5′CGTTA wasavoided for the non-antisense effect that was reported (Tidd et al.,Nucleic Acids Res. 28:2242-2250, 2000).

In another embodiment of the present invention, the complementaryoligonucleotides targeted to the antisense mitochondrial chimeric RNAsor targeted to the sense mitochondrial chimeric RNAs as therapeuticagents to animals or to patients having cancer can induce sensitivity toanti-cancer therapeutic drugs and radiation. Induced sensitivity, alsoknown as sensitization or hypersensitivity, can be measured in tumorcells showing tolerance to anti-cancer therapeutic or radiation. Theanti-cancer drugs comprise those already known in the art and in use oras-yet undiscovered drugs. Among the conventional chemotherapeutic drugsare alkylating agents, anti-metabolite, antibiotics and anti-microtubuleagents. Some examples of these drugs are cisplatin, methotrexate,doxorubicin dactinomycin, mitomycin, cyclophosphamide, etc.

In another aspect of the invention, together or after the treatment ofan animal or a patient having cancer with complementary oligonucleotidestargeted to the antisense mitochondrial chimeric RNA and/or the sensemitochondrial chimeric RNA, the patient can be treated withradiotherapy, wherein said radiotherapy includes ultraviolet radiation,gamma radiation, alpha particles, beta particles, X-ray and electronbeams.

In another aspect of this invention, interference with the function ofthe antisense mitochondrial chimeric RNA or the sense mitochondrialchimeric RNA to induce tumor cell death can be achieved by RNAinterference or RNA silencing. Over the last six years RNA interference(RNAi) has emerged as a novel and promising approach for gene silencingin mammalian cells (Elbashir et al., Nature 411:494-498, 2001; McManuset al., Nature Rev. Genet. 3:737-747, 2002). Synthetically synthesizeddouble stranded RNA molecules of about 19 to 21 nucleotides in lengthhybridize specifically to their complementary target mRNA, leading todegradation of the mRNA and subsequent protein knockdown. Severaldifferent genes have been silenced successfully by small interfering RNAor siRNA (Lu et al., Curr. Opin. Mol. Ther. 5:225-234, 2003; Wacheck etal., Oligonucleotides 13:393-400, 2003). Therefore, synthetic doublestranded RNA of about 19 to 21 nucleotides targeted to the antisensemitochondrial chimeric RNA or to the sense mitochondrial chimeric RNAcan be used to degrade these transcripts and induce tumor cell death.Those familiar in the art will understand that the sequence of the siRNAhas to be complementary to any region of the antisense mitochondrialchimeric RNAs or to the sense mitochondrial chimeric RNAs (SEQ ID NO 1,SEQ ID NO 2, SEQ ID NO 3, SEQ ID NO 4, SEQ ID NO 5, and SEQ ID NO 6).

In another embodiment of the invention, ribozymes can be used tointerfere with the antisense mitochondrial chimeric RNA or with thesense mitochondrial chimeric RNA to induce tumor cell death. Thesequence of the ribozyme has to be designed according to the sequence ofthe antisense mitochondrial chimeric RNA (SEQ ID NO 4, SEQ ID NO 5, SEQID NO 6) or the sense mitochondrial chimeric RNA (SEQ ID NO 1, SEQ ID NO2, SEQ ID NO 3) to cleave specific regions of the transcript that aremore efficient to trigger tumor cell death. Ribozymes are enzymatic RNAmolecules capable of catalyzing the specific cleavage of RNA (Rossi,Curr. Biology 4:469-471, 1994). The mechanism of ribozyme actioninvolves sequence specific hybridization of the ribozyme molecule tocomplementary target RNA, followed by a endonucleolytic cleavage. Thecomposition of ribozyme molecules must include one or more sequencescomplementary to the target gene mRNA, and must include the well knowncatalytic sequence responsible for mRNA cleavage, and described in U.S.Pat. No. 5,093,246, which is incorporated by reference herein in itsentirety. As such, within the scope of the invention hammerhead ribozymemolecules are engineered that specifically and efficiently catalyzeendonucleolytic cleavage of the antisense mitochondrial chimeric RNAs orthe sense mitochondrial chimeric RNAs. The construction and productionof hammerhead ribozymes is well known in the art and it was described(Haseloff et al., Gene, 82:43-52, 1989). Ribozymes of the presentinvention also include RNA endoribonucleases (Zaug et al., Science,224:574-578, 1984).

Gene therapy refers to treatment or prevention of cancer performed bythe administration of a nucleic acid to a patient who has cancer or inwhom prevention or inhibition of cancer is desirable. In this embodimentof the present invention, the therapeutic nucleic acid producedintracellularly is a complementary RNA targeted to the antisensemitochondrial chimeric RNA or to the sense mitochondrial chimeric RNAthat mediates the therapeutic effect by interfering or inhibiting thefunction of these mitochondrial transcripts, inducing tumor cell death.Therefore, one preferred approach is to utilize a recombinant DNAconstruct in which the transcription of the antisense RNA is placedunder the control of strong promoters of RNA polymerase II or III.Expression of the sequence encoding the complementary RNA can be by anypromoter known in the art to act in mammalian, preferably human cells.Such promoters include but are not limited to SV40 early promoter region(Benoist and Chambon, Nature 290:304-310, 1981), the herpes thymidinekinase promoter (Wagner et al., Proc. Natl. Acad. Sci. U.S.A.78:1441-1445, 1981), the regulatory sequences of the metallothioneingene (Brinster et al., Nature 296:39-42, 1982), the promoter of Roussarcoma virus (Yamamoto et al., Cell 22:787-797, 1980), etc. Therecombinant DNA construct to produce the complimentary RNA can be aviral vector which includes, but is not limited to adenovirus vector,adeno-associated virus vector, herpes simplex virus vector, vacciniavirus vector and retrovirus vectors. The vector is introduced in thetarget tumor cells, in a pharmaceutical composition, using methodsfamiliar to those skilled in the art.

Pharmaceutical compositions of the invention comprising an effectiveamount of a complementary nucleic acid (complementary oligonucleotides,siRNA, ribozymes or viral vectors) in a pharmaceutically acceptablecarrier, that can be administered to a patient having cancer tointerfere with the function of the antisense mitochondrial chimeric RNAor the sense mitochondrial chimeric RNA and induce apoptosis of thetumor cells. The complementary nucleic acids may be formulated in apharmaceutical composition, which may include carriers, diluents,buffers, preservatives, surface active agents, polyethylenimide (PEI),liposomes or other lipid formulation known in the art. Thepharmaceutical composition may be administered by topical application,oral, parenteral or rectal administration. Parenteral administrationincludes intravenous, subcutaneous, intraperitoneal or intramuscularinjection or pulmonary administration by inhalation or insufflation.

The compositions of the present invention can be utilized fortherapeutics, diagnostics, prophylaxis and as research reagents andkits.

The compositions and methods provided herein are deemed particularlyuseful for the treatment of cancer. The term cancer as provided herein,includes cells afflicted by any one of the following identifiedanomalous conditions. These include myeloid leukemia acute or chronic,lymphoblastic leukemia acute or chronic, multiple myeloma, Hodgkin'sdisease, non-Hodgkin's lymphoma or malignant lymphoma; stomachcarcinoma, esophagus carcinoma or adenocarcinoma, pancreas ductaladenocarcinoma, insulinoma, glucagonoma, gastrinoma, small boweladenocarcinoma, colorectal carcinomas; hepatocellular carcinoma,hepatocellular adenoma; carcinoids, genitourinary tract such as kidneyadenocarcinoma, Wilm's tumor, bladder and urethra carcinoma and prostateadenocarcinoma, testis cancer like seminoma, teratoma, teratocarcinoma,interstitial cell carcinoma; uterus endometrial carcinoma, cervicalcarcinoma, ovarian carcinoma, vulva and vagina carcinoma,Sertoli-L-eydig cell tumors, melanoma, and fallopian tubes carcinoma;lung, alveolar and bronchiolar carcinomas; brain tumors; skin malignantmelanoma, basal cell carcinoma, squamous cell carcinoma and Karposi'ssarcoma. Also fibrosarcoma, angiosarcoma and rhabdomyosarcoma of theheart and other malignancies that are familiar to these skilled in theart. Thus, the term “cancerous cell” as provided herein, includes a cellafflicted by any one of the above identified conditions.

The following examples serve to describe the manner of using theabove-described invention as well as to set forth the best manner forcarrying out various aspects of the invention. It is understood that inno way these examples meant to limit the scope of this invention, butrather they are presented for illustrative purposes.

Example 1 Isolation and Sequence of the Sense Mitochondrial HumanChimeric RNA (FIG. 1A, SEQ ID NO1)

Initial experiments indicated that the putative human sensemitochondrial chimeric RNA contained a more complex and stable secondarystructure that the mouse chimeric RNA (Villegas et al., DNA & Cell Biol.19:579-588, 2000; Villegas et al., Nucleic Acids Res. 30:1895-1901,2002). Therefore, and based in the mouse mitochondrial chimeric RNAsecondary structure, a theoretical human sense mitochondrial chimericRNA secondary structure was deduced (FIG. 1A). The theoretical humantranscript contained the complete sequence of the sense 16Smitochondrial RNA joined by the 5′ end to a fragment of the antisense16S mitochondrial RNA forming a loop of unknown length (FIG. 1A). Thesegment of the antisense 16S mitochondrial RNA was fully complementaryto the sense 16S mitochondrial RNA and therefore corresponded to aninverted repeat joined to the 5′ end of the sense 16S transcript. Basedon this structure, primers were designed to amplify this putativetranscript by RT-PCR. One reverse primer was at position 11 to 31 fromthe 5′ end of the human sense 16S mitochondrial RNA or at the beginningof the theoretical loop (primer 1, FIG. 1A) (SEQ ID NO 139). Thesequence of the forward primer used was that of positions 213-234 of thesense 16S mitochondrial RNA, and corresponds to primer 3 in FIG. 1A.Amplification of RNA from several human tissues and cells includingHeLa, HL-60, Du145, MCF/7 and human lymphocytes stimulated with PHA (seeExample 7) by RT-PCR using primers 1 and 3 (FIG. 1A), yielded a uniqueamplicon of about 210 bp (FIG. 2). RT-PCR was carried out as describedbefore (Villegas et al., DNA & Cell Biol. 19:579-588, 2000; Villegas etal., Nucleic Acids Res. 30:1895-1901, 2002). The amplicons from eachhuman tissue or cells were cloned and both strands were sequenced. Inall cases, an identical sequence of 216 bp was obtained, containing aninverted repeat of 184 nucleotides joined to the first 31 nucleotides ofthe 5′ end of the sense 16S mitochondrial RNA. Then, we determined ifthe inverted repeat was longer than 184 nucleotides and extended furthertoward the 5′ end of the antisense 16S mitochondrial RNA (FIG. 1A). ThecDNA from HeLa or other cells described before was amplified between thereverse primer 1 positioned at the loop as described before, and primers4 to 7 to walk toward the 5′ end of the putative longer inverted repeat(FIG. 1A). By using this approach, amplification fragments ofapproximately 500, 700 and 800 bp were obtained when primer 1 was usedin combination with primers 4, 5 and 6, respectively. On the other hand,when the cDNA was amplified between primer 1 and primer 7 noamplification product was obtained, suggesting that the 5′ end of theinverted repeat was between primers 7 and 8 (see below). The completesequence of the amplicon of 800 bp reveals an inverted repeat of 769nucleotides joined to the first 31 nucleotides of the sense 16Smitochondrial RNA (SEQ ID NO 1) (FIG. 1A). The sequence at the 3′ end ofthe inverted repeat joined to the sense 16S mitochondrial RNA wasidentical to that found in the same region of the amplicon of 216 bp.This is important because it indicates that in both cases we wereamplifying the same RNA. In addition, the sequence showed that 50nucleotides of the 3′ end of the antisense 16S mitochondrial RNA weremissing in the inverted repeat of the sense mitochondrial cimeric RNA.Altogether, these results suggest that the double stranded structureformed between the inverted repeat and the sense 16S mitochondrial RNAbegins at position 51 of the latter, and forms a putative loop of 50nucleotides.

To confirm the size of the loop, human cDNA was amplified by PCR betweenthe forward primer 2 positioned at the 3′ end of the inverted repeat andprimer 3, which is also reverse at position 213-234 of the sense 16Smitochondrial RNA (FIG. 1A). An amplicon of approximately 240 bp wasobtained and the sequence showed that the first 234 nucleotides of thesense 16 S mitochondrial RNA were joined to the last 25 nucleotides ofthe 3′ end of the inverted repeat. The sequence of the 25 nucleotides ofthe inverted repeat was fully complementary to the sense 16Smitochondrial RNA from positions 51 to 75 (FIG. 1A).

If the sequence of the amplicon obtained with primers 1 and 6 and thesequence of the amplicon obtained with primers 2 and 3 are assembled ascontigs, the emerging structure of the human sense mitochondrialchimeric RNA confirmed a loop of 50 nucleotides and a double strandedstructure of at least 769 bp (FIG. 1A) (see also SEQ ID NO 1).

Since double stranded RNA is not digested by RNase A, the stem of thehuman sense mitochondrial chimeric RNA should be resistant to thisenzyme. On the other hand, the loop or the 3′ region of the sense 16Smitochondrial RNA strand that extended beyond the double strandedstructure should be digested by the enzyme. RNA from HeLa or other cellswas digested with RNase A (50 ug per ml), followed by phenol extraction,and the nuclease-resistant material was recovered by ethanolprecipitation. The cDNA from the digested RNA was then amplified by PCRusing the primers showed in FIG. 1A. The amplicon of about 800 bpobtained with primers 1 and 6 was not amplified after RNase A digestionindicating that the loop was digested by the enzyme. The same was truewith the amplicon of 360 bp obtained with primers 10 and 11 as indicatedin FIG. 1A. Altogether, these results indicated that the loop as well asthe 3′ region of the sense mitochondrial chimeric RNA that extendsbeyond the stem, were digested by the enzyme. On the other hand,amplification of the 750 bp amplicon, corresponding to the doublestranded structure of the sense mitochondrial chimeric RNA and obtainedwith primers 8 and 6, was not affected by the RNase A digestion. Thesequence of the double strand fragment resistant to ribonucleasedigestion was identical with the expected sequence of the stem. The sameresults were obtained after digestion of total RNA from HL-60 cells orother human cells.

To determine the 5′ end of the inverted repeat of the sensemitochondrial chimeric RNA, the stem of the transcript obtained afterRNase A digestion was used for 5′ RACE analysis. The 5′ enddetermination of the inverted repeat was carried out according to themanufacturer's instructions (Invitrogen). The results indicated that theinverted repeat extends for 46 additional nucleotides from the 5′ end ofthe amplicon obtained after amplification of the sense mitochondrialchimeric RNA with primers 1 and 6. In summary, the inverted repeat of815 nucleotides is joined to the 5′ end of the first 865 nucleotides ofthe 16S mitochondrial RNA. The sequence of this transcript showed 99.8%identity with the human 16S mitochondrial gene (H and L strand) (SEQ IDNO 1). The 5′ ends of both extremes of the double stranded stem wereconfirmed by 5′ RACE.

The above results indicated that the sense mitochondrial chimeric RNAcontained a stem or double stranded structure of 815 base pair and aloop of 50 nucleotides. However, these results do not prove that theinverted repeat is joined to the complete 16S sense mitochondrial RNA.The use of conventional approaches such as synthesis of the completecDNA from the 3′ end is useless, since the double stranded structure ofthe transcript represents a insurmountable problem to reversetranscriptases, including Tth (Myers and Gelfand, Biochemistry30:7661-7666, 1991). If the inverted repeat of 815 nucleotides is joinedto the 1559 nucleotides of the 16S mitochondrial RNA one would expect atranscript of 2.3 Kb. Northern blot analysis of total RNA from HeLa,HL-60 and MCF/7 cells were carried out with a probe labeled with ³²P andtargeted to the double stranded structure of the sense mitochondrialchimeric RNA. The results revealed a band of about 2.4 Kb, besides aband of 1.6 Kb, corresponding to the sense mitochondrial chimeric RNAand the sense 16S mitochondrial RNA, respectively. If the RNA wasdigested with RNase A previous to the Northern blot, a singlehybridization band of approximately 0.8 Kb was obtained, whichcorresponds to the size of the stem of the sense mitochondrial chimericRNA. Altogether, these results strongly demonstrated that the sensemitochondrial chimeric RNA contained an inverted repeat of 815nucleotides joined to the 5′ end of the complete sense 16S mitochondrialRNA, and corresponding to SEQ ID NO 1.

It is possible to specifically detect the junction region between theinverted repeat and the sense 16S mitochondrial RNA, using anoligonucleotide probe. The probe has to include 7 to 10 nucleotides ateach side of the joining point between the 3′ end of the inverted repeatand the beginning of the sense 16S mitochondrial RNA. Thisoligonucleotide can be used for in situ hybridization or amplificationby RT-PCR or any other methods familiar to those skilled in the art todetect this novel RNA.

The sense mitochondrial chimeric RNA is present in normal proliferatingcells (human foreskin keratinocytes, spleen, lymphocytes stimulated withPHA, mouse embryos), in pre-cancer cells (keratinocytes transformed withHPV 16 or 18, MT-2 cells transformed with HTLV-1) and in tumor cells. Itis not present in normal resting cells. A summary of these results ispresented in Table 1 (in Example 4).

Example 2 Human Keratinocytes Transformed with Papilloma VirusSynthesize a Novel Sense Mitochondrial Chimeric RNA (FIG. 1B, SEQ ID NO2)

Human foreskin keratinocytes (HFK) were transformed by incubation with alysate of cells previously infected with the human papilloma virus 16(HPV 16). The cells were cultured with 3 parts of K-SFM, one part ofDMEM medium (Invitrogen), 5 ng/ml of EGF, 50 ug/ml of pituitary extractand 10% calf fetal serum. The culture conditions were 37° C. and 5% CO2.After 24 hours of infection, the transformed HFK were transferred to anew flask and grown under the same conditions. After this time the cells(HFK698) were successively transferred to new culture flasks every 3days using a split ratio of 1:3 to 1:4. After passage 19th the cells(HFK698 transformed with HPV 16) were harvested as described (Hausen,Biochim. Biophys. Acta, 1288:F55-F78, 1996), collected by centrifugationat 300×g for 10 min and washed twice with saline phosphate buffer (PBS).Total RNA was extracted from the washed cells with Trizol (Invitrogene).About 200 nanograms of RNA were used to synthesize the cDNA with randomhexamers as described in Example 1. The cDNA was amplified by PCR usingthe reverse primer 1 and the forward primer 3 as described in FIG. 1A.This amplification protocol yielded the expected amplicon of 210 bpwhere the first 31 nucleotides of the sense 16S mitochondrial RNA arejoined to the inverted repeat of 184 nucleotides as described before inExample 1. Electrophoresis analysis of the amplification productsrevealed the presence of the amplicon of 210 base pairs corresponding tothe sense mitochondrial chimeric RNA, plus another amplificationfragment of about 150 base pairs as shown in FIG. 2. The completesequence of this new fragment (SEQ ID NO 2) showed that the initial 31nucleotides from the 5′ end of the sense 16S mitochondrial RNA arejoined to an inverted repeat of 121 nucleotides, which is shorter in 63nucleotides if compared with the inverted repeat of the sensemitochondrial chimeric RNA of SEQ ID NO 1. This shorter inverted repeatgenerates a longer loop of 96 nucleotides (FIG. 1B) in the structure ofthe mitochondrial chimeric RNA. The remaining of the sequence isidentical to SEQ ID NO 1). This novel sense mitochondrial chimeric RNAis not present in SiHa cells (FIG. 4A), which are tumorigenic cellstransformed with HPV 16, nor in normal proliferating human cells likehuman lymphocytes stimulated with PHA (see Example). Similar resultswere obtained with HFK transformed with HPV 18 or 18Nco cells. The cellstransformed or immortalized (but not tumorigenic) with HPV 16 or HPV 18are considered as pre-malignant cells and therefore the novel sensemitochondrial chimeric RNA is a new potential marker for pre-malignantcells.

Since the sequence of the 3′ end of the inverted repeat of SEQ ID NO 2joined to the 16S mitochondrial RNA is different to the same region ofSEQ ID NO 1, an oligonucleotide probe can be used for the specificdetection of this transcript. The probe has to include 7 to 10nucleotides at each side of the joining point between the 3′ end of theinverted repeat and the beginning of the sense 16S mitochondrial RNA,such as the oligonucleotide of SEQ ID NO 7. This oligonucleotide can beused for in situ hybridization or amplification by RT-PCR or any othermethods familiar to those skilled in the art to detect this novel andspecific marker of pre-cancer cells.

Example 3 Cells Transformed with HTLV-1 Induce the Expression of a ThirdNovel Sense Mitochondrial Chimeric RNAs (FIG. 1C, SEQ ID NO 3)

Human MT-2 cells transformed with HTLV-1 were cultured as described(Kobayashi et al., EMBO J., 3:1339-1343, 1984). The cells wereharvested, centrifuged at 300×g for 10 min and washed twice with PBS.The final cell pellet was extracted with Trizol as described inExample 1. The cDNA was synthesized with random hexamers using the RNAas template and the cDNA was amplified by PCR using the reverse primer 1and the forward primer 3 as described in FIG. 1A. As described before,this amplification protocol yields an amplicon of 210 base pair thatcontains the first 31 nucleotides of the sense 16S mitochondrial RNAjoined to an inverted repeat of 184 nucleotides which corresponds to thesense mitochondrial chimeric RNA as described in Example 1.Electrophoresis analysis of the amplification products revealed, besidesthe presence of the already discussed amplicon of 210 base pair, a bandof about 150 base pair (see FIG. 2). The sequence of the amplicon of 150base pair is identical to the sequence of the amplicon described inExample 2, corresponding to a second sense mitochondrial chimeric RNAexpressed in cells transformed with HPV 16 or HPV 18 (SEQ ID NO 2). Inaddition, a new amplification product was found of about 100 bp (FIG.2). The sequence of this third amplicon revealed an inverted repeat of61 nucleotides joined to the 5′ end of the sense 16S mitochondrial RNAand generating a loop of 167 nucleotides (FIG. 1C; SEQ ID NO 3). Thisnovel amplicon was not present in normal cells, in tumor cells and incells transformed with HPV 16 or 18. Therefore, this new sensemitochondrial chimeric RNA is a potential marker of cells transformedwith the oncogenic retrovirus HTLV-1.

Since the sequence of the 3′ end of the inverted repeat of SEQ ID NO 3joined to the 16S mitochondrial RNA is different to the same region ofSEQ ID NO 1 and SEQ ID NO 2, an oligonucleotide probe can be used forthe specific detection of this transcript. The probe has to span between7 to 10 nucleotides at each side of the joining point between the 3′ endof the inverted repeat and the beginning of the sense 16S mitochondrialRNA, such as oligonucleotide of SEQ ID NO 8. This oligonucleotide can beused for in situ hybridization or amplification by RT-PCR or any othermethods familiar to those skilled in the art to detect this specificmarker of cells transformed with a retroviral oncogenic virus.

Example 4 Structure of the Human Antisense Mitochondrial Chimeric RNA

Our initial experiments indicated that a second family of chimeric RNAscorresponding to the antisense mitochondrial chimeric RNA was present insome of the cells studies. To establish the structure of the humanantisense mitochondrial chimeric RNA, the strategy used for the sensemitochondrial chimeric RNA was employed (FIG. 1). The theoreticalantisense mitochondrial chimeric RNA contained a fragment of the sense16S mitochondrial RNA as inverted repeat joined to the 5′ end of theantisense 16S mitochondrial RNA. The latter RNA is transcribed from theL-strand of the mitochondrial DNA and corresponds to the 16Smitochondrial gene (FIG. 3). To amplify this RNA, a reverse primer washybridized close to the 5′ end of the antisense 16S mitochondrial RNAand forward primers were hybridized at different positions of theputative fragment of the inverted repeat (FIG. 3). Total RNA from humanlymphocytes stimulated with PHA for 48 h was used as template. The cDNAwas synthesized with random hexamers as described in Example 1.Amplification of the cDNA by PCR was carried out with the reverse primerpositioned close to the beginning of the 5′ end of the antisense 16Smitochondrial RNA (primer 1, FIG. 3) and different forward primerspositioned on the inverted repeat (FIG. 3). Only three major ampliconswere obtained which differed in the size of the inverted repeat and thesize of the loop. These amplicons were purified and sequenced. One ofthese antisense mitochondrial chimeric RNA contains an inverted repeatof 365 nucleotides and a loop of 17 nucleotides (SEQ ID NO 4). AnotherRNA contains a loop of 96 nucleotides and an inverted repeat of 189nucleotides (SEQ ID NO 5). Yet, another specie of the antisensemitochondrial chimeric RNA contains an inverted repeat of 296nucleotides and a loop of 451 nucleotides (SEQ ID NO 6). The sequencesof all three antisense mitochondrial chimeric RNAs were 99.8 percenthomologous with the sequence of the mitochondrial DNA gene (H and Lstrand).

The results, which will be presented in the following examples indicatethat there is a major difference between pre-tumor and tumor cells andnormal proliferating cells with respect to the expression of theantisense mitochondrial chimeric RNA. All proliferating cellsoverexpress the sense mitochondrial chimeric RNA. However, while normalproliferating cells also express the antisense mitochondrial chimericRNAs, these transcripts are down regulated in tumor cells.Non-proliferating or resting cells do not express either mitochondrialchimeric RNAs. Therefore, the differential expression of these RNArepresents a novel and powerful marker of carcinogenesis, which can bedetected by in situ hybridization, Northern blot analysis, RT-PCR or TMAor other techniques known by one skilled in the art.

A summary of the differential expression of the sense and antisensemitochondrial chimeric RNAs is shown in Table 1.

TABLE 1 Expression of the chimeric RNAs in different type of cells.Normal Transformed Chimeric Normal Prolif- Transformed with RNAs Restingerating with HPV HTLV-1 Cancer SEQ ID NO 1 −− +++++ +++++ +++++ +++++SEQ ID NO 2 −− −− ++++ ++++ −− SEQ ID NO 3 −− −− −− ++++ −− SEQ ID NO 4−− +++++ +/− +/− +/− SEQ ID NO 5 −− +++++ +/− +/− +/− SEQ ID NO 6 −−+++++ +/− +/− +/− + and −: relative level of expression by in situhybrization

Example 5 Tumor Cells Lines Over Express the Sense MitochondrialChimeric RNA (SEQ ID NO 1) and Down Regulate the Expression of theAntisense Mitochondrial Chimeric RNA (SEQ ID NOS 4, 5 and 6)

In situ hybridization was used to determine the expression of the sensemitochondrial chimeric RNA in tumor cell lines in culture. For in situhybridization, adherent tumor cells were cultured in 8-wells chamberslides (Lab-Tek®, NUNC) for 24 to 48 h at 37° C., using the appropriatemedium and conditions recommended by American Tissue Culture Collectionor ATCC. For non-adherent cells (e.g. HL-60, Jurkat and Ramos), theywere cultured in small flask for 48 hours at 37° C. The cells wererecovered by centrifugation at 300×g for 10 min, resuspended in smallvolume of PBS and aliquots of 10 to 20 ul were applied on glass slidespreviously coated with polylysine or an adhesive protein purified frommussels (Burzio et al, Curr. Opin. Biotechnol., 8:309-312, 1997). Thecells were dried at room temperature for 30 min.

The cells were washed three times with PBS and fixed with 4%para-formaldehyde for 10 min at room temperature. The slides were thenwashed three times with PBS for 5 min and incubated with 0.2 N HCl for10 min at room temperature. The cells were washed again three times,first with PBS and then with 2×SSC for 10 min (2×SSC: 0.3 M NaCl, 30 mMsodium citrate, pH 7.0) (Sambrook et al., 1989) at room temperature. Theprehybridization was carried out for 30 min at 37° C. in a solutioncontaining 4×SSC, 10% dextran sulfate, 150 μg/ml yeast tRNA and herringsperm DNA, 50% formamide and 1×Denhardt solution (0.2 mg/ml Ficoll type400, 0.2 mg/ml polyvinyl pyrrolidone, 0.2 mg/ml BSA). Hybridization wascarried out for 15 hours at 37° C. in the same prehybridization mixturecontaining 3.5 pmoles of probes targeted to the sense and antisensemitochondrial chimeric RNAs. The probes contained 20 or moredeoxynucleotides targeted to different regions of the sequence of thesense or antisense mitochondrial chimeric RNA (see SEQ ID NO 98 to 196and SEQ ID NO 9 to 97, respectively). The probes were previously labeledat the 3′ end with digoxigenin-11-dUTP (Roche) and terminal transferase(Promega) as described before (Villegas et al., DNA & Cell Biol.,19:579-588, 2000). To eliminate the excess of probe, the slides werewashed first with 2×SSC for 10 min and with 1×SSC for 10 min at roomtemperature. Then the samples were washed with 0.2×SSC for 30 min at 45°C. and finally, with 0.2×SSC for 10 min at room temperature.

After hybridization, the cells were incubated for 30 min in blockingbuffer (1% BSA, 0.3% Triton X-100 in PBS) and then incubated for 2 h atroom temperature with anti-digoxigenin monoclonal antibody conjugated toalkaline phosphatase (Roche), previously diluted 1:500 in the blockingbuffer. Finally, the slides were washed twice with PBS and the colorreaction was carried out with a BCIP/NBT substrate mixture (DAKO) asdescribed before (Villegas et al., DNA & Cell Biol., 19:579-588, 2000).The same procedure was employed for FISH, using anti-digoxigeninantibodies conjugated with fluorescein or rhodamine.

As shown in FIGS. 4A and 4B, in situ hybridization with a probe labeledwith digoxigenin corresponding to SEQ ID NO 63 reveals that human tumorcells overexpress the sense mitochondrial chimeric RNA. In situhybridization with the sense probe labeled with digoxigenin andcorresponding to SEQ ID NO 64 was negative (FIGS. 4A and B) indicatingdown regulation of the expression of the antisense mitochondrialchimeric RNA. The same results were obtained with oligonucleotide probestargeted to other regions of the sense or antisense mitochondrialchimeric RNA.

Example 6 Tumor Cells in Human Biopsies Over Express the SenseMitochondrial Chimeric RNA (SEQ ID NO 1) and Down Regulate the AntisenseMitochondrial Chimeric RNA (SEQ ID NOS 4, 5 and 6)

Human biopsies were obtained from pathologists or tissue arrays fromDAKO. Most of the samples analyzed were paraffin-embedded and fixed withformalin. Other tissue samples were fixed with Boiun's fixative andanother samples were fresh frozen tissue sections. The tissue sectionsof about 4 to 8 μm were fixed on slides previously coated withpolylysine or the adhesive polyphenolic protein purified from the musselAulacomya ater (Burzio et al., Curr. Opin. Biotechnol., 8:309-312,1997). The paraffin-embedded tissue sections were incubated for 1 h at60° C., and the paraffin was removed by three washes with xylol for 15min each time. The sections were air dried and washed four times withPBS. Then the sections were incubated with 0.2 N HCl for 10 min at roomtemperature and then thoroughly washed with PBS. Afterwards, the sampleswere subjected to in situ hybridization with the antisense probeslabeled with digoxigenin according to protocol described in Example 4. Aparallel section was hybridized with a sense probe corresponding to thesame region of the sense mitochondrial chimeric RNA.

As shown in FIG. 5A, the cells present in tumors of breast, uterinecervix, bladder and lung carcinoma revealed a strong staining with theantisense probes targeted to the sense mitochondrial chimeric RNA,indicating strong presence of the transcript. On the other hand the insitu hybridization with the probe targeted to the antisensemitochondrial chimeric RNA was negative, indicating down regulation ofthis transcript (FIG. 5A). Other tumors also over express the sensemitochondrial chimeric RNA, and down regulate the expression of theantisense mitochondrial chimeric RNA (FIG. 5B).

Example 7 Normal Proliferating Cells Over Express the Sense and theAntisense Mitochondrial Chimeric RNAs

Using the same protocol for in situ hybridization described in Examples5 and 6, the expression of the sense mitochondrial chimeric wasdetermined in proliferating cells. As shown in FIG. 6, HFK cells,spermatogonia, spleen cells and proliferating cells of mouse embryo,showed strong hybridization signal indicating over expression of thesense mitochondrial chimeric RNA. In contrast, non-proliferating cellssuch as cells of the brain, muscle and liver show no signal indicatingthat the sense mitochondrial chimeric RNA is not expressed or is downregulated in these cells.

However, the surprising result was that when the in situ hybridizationwas carried out with probes targeted to the antisense mitochondrialchimeric RNA, a strong signal was also observed (FIG. 6). Severalcontrols assayed in parallel indicated that the hybridization signalwith these probes was not due to an artifact. The hybridization signaldisappeared if the in situ hybridization was carried out with thelabeled probe together with an excess (50 to 100 times) of the sameprobe but non-labeled with digoxigenin. If previous to the hybridizationthe samples were incubated with ribonuclease A overnight, thehybridization signal disappeared. Also, no hybridization signal wasobserved if the hybridization was carried out with a labeled probetargeted to the antisense mitochondrial chimeric RNA with 4 mistmaches.

Example 8 Normal Human Lymphocytes Stimulated with Phytohemagglutinin(PHA) Overexpress the Sense and the Antisense Mitochondrial ChimericRNAs

Five ml of blood from healthy donors were collected with EDTA. The bloodwas diluted with one volume of 0.9% NaCl and the mixture was applied on5 ml of Histopaque-1077 (Sigma) in a centrifuge tube. The tubes werecentrifuged at 800×g for 20 min at room temperature. The white cells atthe interphase were collected, diluted with 2 volumes of 0.9% NaCl andcentrifuged at 250×g for 10 min at room temperature. The collected cellswere suspended and washed twice with RPMI 1640 medium supplemented with200 mM glutamine, 10 mM non-essential amino acids, penicillin,streptomycin devoid of calf fetal serum. The final sediment wasresuspended in the same medium with 10% calf fetal serum and the numberof human lymphocytes per ml was determined by counting under themicroscope in a Neubauer chamber.

Human lymphocytes were cultured in 96-wells microtiter plates with theRPMI 1640 medium supplemented as described plus 10% calf fetal serum at37° C. and with 5% CO2. About 30,000 lymphocytes per well were culturedwith or without 10 ug per ml of the mitogen PHA, which induce cellproliferation (Yu et al., J. Biol. Chem., 266:7588-7595, 1991). After 48to 72 h of treatment with PHA, the cells are actively engaged in DNAsynthesis as demonstrated by the incorporation of H3-thymidine or BrdU(Yu et al., J. Biol. Chem., 266:7588-7595, 1991). Also, 48 hours afterstimulation with PHA, the lymphocytes overexpressed other markers ofcell proliferation such as the proliferating cell nuclear antigen orPCNA and Ki-67 (Bantis et al., Cytopathology, 15:25-31, 2004) (FIG. 7).The resting or control lymphocytes did not express these antigens (FIG.7).

To determine if the stimulated lymphocytes expressed the sensemitochondrial chimeric RNAs, the cells were subjected to in situhybridization with oligonucleotide probes labeled with digoxigenin andtargeted to the sense mitochondrial chimeric RNA. The in situhybridization protocol employed was described in Example 5. A stronghybridization signal was obtained indicating overexpression of thistranscript (FIG. 7). The hybridization signal was similar in intensityto that observed on tumor cells or other normal proliferating cells(compare FIG. 7 with FIGS. 4 A and B, FIGS. 5A and B). No hybridizationsignal was observed on the control lymphocytes incubated without PHA(FIG. 7).

When the in situ hybridization was carried out with senseoligonucleotide probes labeled with digoxigenin and targeted to theantisense mitochondrial chimeric RNA, an equally strong hybridizationsignal was obtained (FIG. 7). Several controls were carried out todiscard the possibility that the hybridization signal was due toartifacts. The hybridization signal disappears if the in situhybridization is carry out with the sense labeled probe together withexcess (50 to 100 times) of the same sense probe but unlabeled withdigoxigenin. If previous to the hybridization the samples are incubatedwith ribonuclease A overnight, the hybridization signal disappears.Also, no hybridization signal is observed if the hybridization iscarried out with sense probes with 4 mistmaches. In contrast, in situhybridization of non-stimulated lymphocyte showed no hybridizationsignal (FIG. 7). In conclusion, normal human lymphocytes stimulated toproliferate overexpress both, the sense mitochondrial chimeric RNA andthe antisense mitochondrial chimeric RNA. These transcripts are notexpressed in resting cells.

Example 9 The Sense Mitochondrial Chimeric RNA Exhibits DifferentLocalizations in Normal and Tumor Cells

The in situ hybridizations reported in Examples 5 and 6, indicated thatin several tumor cell lines as well as in tumor cells of human biopsies,the sense mitochondrial chimeric RNA is localized preferentially in thecytoplasm. However, in some tumor biopsies a clear localization of thetranscripts in the nucleus was also found (FIG. 4 A, B).

A surprising finding was the localization of the sense mitochondrialchimeric RNA in the nucleolus. In situ hybridization carried out asreported in Example 5, revealed positive hybridization signal in thenucleolus of HeLa and SiHa cells (FIG. 8). The hybridization signal wasstronger in the nucleolus of HFK transformed with HPV 16 (FIG. 8). Thenucleolar localization has been also found in tumor cells from breasttumors and rhabdomiosarcoma (FIG. 8).

Co-localization studies indicated that the sense mitochondrial chimericRNA localized in the cytoplasm is outside the mitochondria andassociated to late endosomes/lysosomes. If co-localization studies arecarried out with markers of mitochondria such as Mitotrack (MolecularProbes), or antibodies anti-cytochrome c (Promega) or anti-EndonucleaseG (Chemicon), the in situ hybridization showed a poor co-localization.However, a perfect co-localization was found between the hybridizationsignal with the immunocytochemistry of late endosemes/lysosomes markerssuch as Lysotrack (Molecular Probes), or antibodies anti-Lamp-2 (BDPharmigen) or anti-cathepsin D (Zymed).

HeLa cells were subjected to in situ hybridization with oligonucleotideprobes labeled with digoxigenin as described in Example 5. Afterpost-hybridization and the whashing procedures, the cells were incubatedwith an anti-digoxigenin antibody labeled with rhodamine (Roche) and ananti-Lamp-2 antibody labeled with fluoresceine (BD Pharmingen). Afterincubation at room temperature for 3 h in the dark, the slides werewashed, mounted and analyzed with a Zeiss confocal microscope. A clearco-localization of the hybridization signal with the localization ofLamp-2 was obtained. Similar co-localization results of thehybridization signal were obtained when Lysotrack or anti-cathepsin Dantibodies were used as markers of the lysosomal fraction. As far as weknow, this is the first report showing that a RNA (specially amitochondrial transcript) is associated to the lysosomes of the cell.Determination of the localization of the sense mitochondrial chimericRNA in tumor cells may have an important prognostic values for patientswith cancer. In general, in normal proliferating cells, the sense andthe antisense mitochondrial chimeric RNAs are mainly localized in thenucleus.

Example 10 Treatment of Tumor Cells In Vitro with AntisenseOligonucleotides Targeted to the Antisense Mitochondrial Chimeric RNAInduces Cell Death

HL-60 cells were cultured under the optimal conditions recommended byATCC. About 30,000 cells were cultured in 96-well microtiter plates.Oligonucleotides (2 uM) targeted to the sense or to the antisensemitochondrial chimeric RNA were added. To enhance the permeability ofthe cells, the oligonucleotides were added in mixture with lipofectaminor oligofectamin (Invitrogen) or with polyethylenimide (PEI) (—ExgenTM500, Fermentas). PEI was preferred because is practically non-toxic tothe cells. The cells were incubated with the oligonucleotides for 6 hand the percentage of cell survival was determined by permeability totrypan blue. After 6 h incubation with the oligonucleotides an importantpercentage of the cells died. However, oligonucleotides targeted to theantisense mitochondrial chimeric RNA were more effective to induce celldeath (about 90% versus 15% of cell death). On the other hand, noapoptosis was induced when the cells were treated with oligonucleotidestargeted to the sense or antisense 12S mitochondrial RNA or the mRNA ofND1 subunit or with scrambled oligonucleotides or oligonucleotides withfour mismatches, all of which were used as controls. Theoligonucleotides used in these studies contain phosphorothioate linkagein the first 5 nucleotides at the 5′ end and the last five nucleotidesat the 3′ end. On the average, the 10 central nucleotides containphosphodiester bonds.

To establish if the treatment of the cells with these oligonucleotidesinduces DNA fragmentation, HL-60 cells were incubated under the sameconditions described before with oligonucleotides for 6 h. About 30,000HL-60 cells were cultured in 200 ul of IDMEM plus 10% calf fetal serumin 96-wells microtiter plate together with 1 uM of oligonucleotidestargeted to the sense mitochondrial chimeric RNA or targeted to theantisense mitochondrial chimeric RNA. The chemistry of theoligonucleotides added in mixture with PEI was the same described in theprevious section. After an incubation of 6 h with the oligonucleotidesthe cells were assayed for DNA fragmentation using the TUNEL assay(DeadEnd Colorimetric TUNEL System, Promega). As shown in Table 2, about96% of the cells showed DNA fragmentation after treatment with theoligonucleotide targeted to the antisense mitochondrial chimeric RNA.Similar rate of DNA fragmentation was obtained with the drugstaurosporine. Scrambled oligonucleotides or oligonucleotides withmismatches showed no effect. In contrast, only about 20% of the cellsdied when treated with oligonucleotide targeted to the sensemitochondrial chimeric RNA (Table 2). As shown previously, tumor cellsdown regulate the expression of the antisense mitochondrial chimeric RNAand consequently these cells carry a low number of copies of thistranscript. Therefore, cell death is more efficiently induced witholigonucleotides targeted to the antisense mitochondrial chimeric RNA.These results strongly suggest that the low number of copies of theantisense mitochondrial chimeric RNA in tumor cells constitute a targetfor therapy.

TABLE 2 Oligonucleotides complementary to the antisense mitochondrialchimeric RNA induce apoptosis in HL-60 cells. Percent of apoptotic cellsTreatment Assayed by TUNEL Control 3.0% Oligonucleotides complementaryto the 96.7% antisense chimeric RNA Mismatch oligonucleotides 4.0%Scrambled oligonucleotides 3.5% Oligonucleotides complementary to the26.7% sense chimeric RNA Staurosporine 98.4% Oligonucleotidescomplementary to the 3.7% sense 12 S mitochondrial RNA Oligonucleotidescomplementary to the 4.1% antisense 12 S mitochondrial RNA

In another study, we determined if the treatment of the cells witholigonucleotides targeted to the antisense mitochondrial chimeric RNAinduced caspases activation. Caspases are proteolytic enzymes, activelyinvolved in programmed cell death or apoptosis. HL-60 were incubatedwith oligonucleotides targeted to the antisense mitochondrial chimericRNA or with staurosporin for 6 h under the culturing conditionsdescribed before. Then, VAD-fmk (CaspaCe FITC-VAD-FMK, Promega)conjugated with fluorescein was added to the culture and incubated for30 min at 37° C. VAD-fmok is strong inhibitor of caspases and binds tothe proteases with very high affinity (Gracia-Calvo et al., J. Biol.Chem., 273:32608-32613, 1998). The cells were washed by centrifugation,mounted and observed with a fluorescence microscope. As shown in FIG. 9,HL-60 cells treated with the oligonucleotide targeted to the antisensemitochondrial chimeric RNA induced activation of caspases, at similarlevel to the activation achieved with staurosporine. No activation ofcaspases was obtained with antisense oligonucleotides targeted to the12S mitochondrial RNA used as control.

The cells treated with oligonucleotides targeted to the antisensemitochondrial chimeric RNA also exhibit other changes that are congruentwith apoptosis. Electron microscopy analysis showed nuclearfragmentation and chromatin condensation. Nuclear fragmentation was alsodemonstrated by staining of the nuclei with DAPI. After treatment withthese oligonucleotides targeted to the antisense mitochondrial chimericRNA, the cells undergo nuclear fragmentation as revealed by DAPIstaining (FIGS. 9E and 9F).

Example 11 Other Tumor Cells Also Undergo Cell Death when Treated withOligonucleotides Complementary to the Antisense Mitochondrial ChimericRNA

Other tumor cells were treated with oligonucleotides complementary tothe antisense mitochondrial chimeric RNA according to the protocoldescribed in Example 10. The cells were incubated in their optimalcondition according to the recommendation of ATCC, and 2 uMoligonucleotide was added at the initial period of the experimenttogether with PEI. Six hours later a second addition of theoligonucleotide was carried out at the same concentration and the effectwas determined 15 h after the initiation of the experiment. Cell deathwas determined by DAPI staining and counting the number of cells withfragmented nuclei. As shown in Table 3, over 70% of the cells treatedwith oligonucleotides undergo apoptosis. It is important to notice, thatmelanoma cells, lymphoma cells and the breast carcinoma cells MCF/7,known to be quite resistant to drug treatment, undergo apoptosis at avery high rate (Table 3)

TABLE 3 Induction of apoptosis in tumor cell lines by treatment witholigonucleotides complementary to the antisense mitochondrial chimericRNA. Percent of Apoptotic Cells* Cells (DAPI staining) MCF/7 89% ± 9Melanome 4295 86% ± 7 Hep G2 93% ± 3 Hela 91% ± 5 DU145 89% ± 6 Lymphomacells Devernelle 87% ± 5 Caco-2 64% ± 7 *Treatment was for 15 h and 2 uMoligonucleotides. Apoptosis in cells treated with scrambled or mismatcholigonucleotides, or without oligonucleotides varies between 3 to 10%.

To determine if there are regions in the transcript that are moreefficient targets for the oligonucleotides in inducing apoptosis thefollowing experiments were carried out. The induction of apoptosis wasstudied in Hela, HL-60 and MCF/7 cells with antisense oligonucleotidesof about 20 nucleotides, targeted about every 30 nucleotides startingfrom the 5′ end of the antisense mitochondrial chimeric RNA. At timezero 1 uM oligonucleotides were added together with PEI and thistreatment was repeated 6 h later. Fifteen hours after the beginning ofthe treatment, the percent of cell undergoing apoptosis was determinedby staining with DAPI and counting the cells with fragmented nuclei.Although most of the oligonucleotides induced a variable degree ofapoptosis, the single stranded region of the antisense mitochondrialchimeric RNA was a better target to induce cell death. Theoligonucleotides targeted to the putative double stranded or loopstructure of the antisense mitochondrial chimeric RNAs were lesseffective.

Apoptosis can also be determined by trypan blue staining, propidiumiodide staining, anexine immunochemistry. In these techniques, the cellscan be analyzed by fluorescent microscopy or by flow cytometry. DNAfragmentation can be measured by TUNEL or by electrophoresis to revealthe ladder of DNA. Western blot analysis can also be used to determinethe processing of proteins such as caspases, poly (ADP-Rib) synthase,etc.

Example 12 Treatment of Normal Proliferating or Resting Cells withOligonucleotides Complementary to the Antisense Mitochondrial ChimericRNA are Refractory to Apoptosis

As described before, normal proliferating cells overexpress the sensemitochondrial chimeric RNA as well as the antisense mitochondrialchimeric RNA. Resting cells, on the other hand, are not expressingneither of these transcripts. Therefore, it was important to determineif oligonucleotides complementary to the antisense mitochondrialchimeric RNA induce cell death in normal cells.

Human lymphocytes were stimulated with 10 ug per ml of PHA for 48 h asdescribed in Example 8. In parallel, control lymphocytes were incubatedalso for 48 h but without PHA. At 48 h of culture, 15 uM ofoligonucleotide mixed with PEI (see Example 10) was added to thestimulated and control lymphocytes and further incubated with 15 h. Theconcentration of the oligonucleotide was 10 fold higher than theconcentration used in previous experiments (1-2 uM). Other samples ofstimulated or control lymphocytes were treated with 0.4 uM staurosporinefor the same period of time. At the end of the experiment, cell deathwas measured by either trypan blue staining or DAPI staining. As shownin FIG. 10, control lymphocytes or lymphocytes stimulated with PHAincubated for 15 h without oligonucleotide showed a similar level ofspontaneous apoptosis that varied between 7 to 10% in differentexperiments. A similar result was obtained with a lower (1-2 uM)concentration of oligonucleotide. Also, control and stimulatedlymphocytes incubated with 15 uM antisense oligonucleotide for 15 hshowed similar low level of apoptosis (around 10%) (FIG. 10). Incontrast, control lymphocytes or lymphocytes stimulated with PHA andincubated with staurosporine also for 15 h showed that over 80% of thecells undergo apoptosis (FIG. 10). This is a very important resultbecause shows that normal resting cells or normal proliferating cellssuch as human lymphocytes are refractory to induction of apoptosis bythe oligonucleotides complementary to the antisense mitochondrialchimeric RNA. In other words, induction of apoptosis in tumor cells byinterfering with the antisense mitochondrial chimeric RNA is a selectivetherapeutic approach for cancer.

REFERENCES

-   1. Adrain et al., “Regulation of apoptotic protease activating    factor-1 oligomerization and apoptosis by the WD-40 repeat region”,    J Biol Chem. 274:20855-20860, 1999.-   2. Bantis et al., “Expression of p129, Ki-67 and PCNA as    proliferation markers in imprint smears of prostate carcinoma and    their prognostic value”, Cytopathology, 15:25-31, 2004.-   3. Beaucage, “Oligodeoxyribonucleotides synthesis. Phosphoramidite    approach”, Methods Mol. Biol. 20:33-61, 1993.-   4. Benedict et al., “Expression and functional analysis of Apaf-1    isoforms. Extra Wd-40 repeat is required for cytochrome c binding    and regulated activation of procaspase-9”, J Biol Chem.    275:8461-8468, 2000.-   5. Benoist and Chambon, “In vivo requirement of the SV40 early    promoter region”, Nature 290:304-310, 1981.-   6. Boya et al., “Mitochondrion-targeted apoptosis regulators of    viral origin”, Biochem. Biophys. Res. Commun. 304:575-581, 2003.-   7. Brinster et al., “Regulation of metallothionein-thymidine kinase    fusion plasmids injected into mouse eggs”, Nature 296:39-42, 1982.-   8. Burzio et al., “Environmental bioadhesion: themes and    applications”, Curr. Opin. Biotechnol., 8:309-312, 1997.-   9. Capaldi et al., “Highly efficient solid phase synthesis of    oligonucleotide analogs containing phosphorodithioate linkages”,    Nucleic Acids Res. 28:E40, 2000.-   10. Carew and Huang, “Mitochondrial defects in cancer”, Mol. Cancer,    1:1-12, 2002.-   11. Celis, “Cell Biology, A Laboratory Handbook”, Julio E. Celis,    ed., 1994-   12. Chinnery and Turnbull, “Mitochondrial DNA mutations in the    pathogenesis of human disease”, Mol. Med. Today, 6:425-432, 2000.-   13. Clayton and Vinograd, “Circular dimer and catenate forms of    mitochondrial DNA in human luekaemic leucocytes”, Nature,    216:652-657, 1967.-   14. Clayton and Vinograd, “Complex mitochondrialDNA in leukemic and    normal human myeloid cells”, Proc. Natl. Acad. Sci. US,    62:1077-1084, 1969.-   15. Clayton, “Transcription and replication of mitochondrial DNA”,    Hum Reprod. Suppl 2:11-17, 2000.-   16. Comanor et al., “Successful HCV genotyping of previously failed    and low viral load specimens using an HCV RNA qualitative assay    based on transcription-mediated amplification in conjunction with    the line probe assay.”, J. Clin Virol., 28:14-26, 2003.-   17. Egholm et al., “PNA hybridizes to complementary oligonucleotides    obeying the Watson-Crick hydrogen-bonding rules”, Nature,    365:566-568, 1993.-   18. Elbashir et al., “Duplexes of 21-nucleotides RNAs mediate RNA    interference in cultured mammalian cells,” Nature 411:494-498, 2001.-   19. Falkenberg et al., “Mitochondrial transcription factors B1 and    B2 activate transcription of human mtDNA”, Nat Genet. 31:289-294,    2002.-   20. Ferri and Kroemer, “Organelle-specific initiation of cell death    pathways”, Nature Cell Biol. 3:E255-263, 2001.-   21. Frederick et al., in “Current Protocols In Molecular Biology”,    Volume 2, Unit 14, Frederick M. Ausubul et al. eds., 1995.-   22. Gracia-Calvo et al., “Inhibition of human caspases by    peptide-based and macromolecular inhibitors”, J. Biol. Chem.,    273:32608-32613, 1998.-   23. Guicciardi et al., “Lysosomesin cell death”, Oncogene,    23:2881-2890, 2004.-   24. Haseloff et al., “Sequence required for self-catalysed cleavage    of the satellite RNA of tobacco ringspot virus”, Gene, 82:43-52,    1989.-   25. Hausen, “Papillomavirus infection—a major cause of human    cancer,” Biochim. Biophys. Acta, 1288:F55-F78, 1996.-   26. Hedge et al., “Commitment to apoptosis induced by tumour    necrosis factor-alpha is dependent on caspase activity”, Apoptosis,    7:123-132, 2002.-   27. Hyrup and Nielsen, “Peptide nucleic acids (PNA): synthesis,    properties and potential applications”, Bioorg. Med. Chem., 4:5-23,    1996.-   28. Johnstone et al., “Apoptosis: a link between cancer genetics and    chemotherapy”, Cell 108:153-164, 2002.-   29. Kobayashi et al., “Genomic structure of HTLV: detection of    defective genome and its amplification in MT2 cells”, EMBO J.,    3:1339-1343, 1984-   30. Komarov et al., “A chemical inhibitor of p53 that protect mice    from the side effects of cancer therapy”, Science 285:1733-1737,    1999.-   31. Krammer, “CD95's deadly mission in immune system”, Nature    407:789-795, 2000.-   32. Li et al., “Endonuclease G is an apoptotic DNase when released    from mitochondria”, Nature, 412:95-99, 2001.-   33. Liu et al., “Synthetic peptides and non-peptidic molecules as    probes of structure and function of Bcl-2 family proteins and    modulators of apoptosis”, Apoptosis, 6:453-462, 2001.-   34. Lu et al., “siRNA-meditated antitumorogenesis for drug target    validation and therapeutics,” Curr. Opin. Mol. Ther. 5:225-234,    2003.-   35. Mag et al., “Synthesis and selective cleavage of an    oligodeoxynucleotide containing a bridged internucleotide    5′-phosphorothioate linkage”,-   36. Martins et al., “The serine protease Omi/HtrA2 regulates    apoptosis by binding XIAP through a reaper-like motif”, J. Biol.    Chem. 277:439-444, 2002.-   37. McCulloch et al., “A human mitochondrial transcription factor is    related to RNA adenine methyltransferases and binds    S-adenosylmethionine”, Mol. Cell Biol. 22:1116-1125, 2002.-   38. McKay et al., “Characterization of a potent and specific class    of antisense oligonucleotide inhibitor of human protein kinase C-α    expression”, J. Biol. Chem., 274:1715-1722, 1999.-   39. McKinnell et al., “The Biological Basis of Cancer, (R. G.    McKinnell, R. E. Parchment, A. O. Perantoni, G. B. Pierce, eds.),    Ch.3, Cambridge University Press, UK, 1998-   40. McManus et al., “Gene silencing in mammals by small interfering    RNAs,” Nature Rev. Genet. 3: 737-747, 2002.-   41. Meier et al., “Apoptosis in development”, Nature 407:796-801,    2000.-   42. Myers et al., “Reverse transcription and DNA amplification by a    Thermus thermophilus DNA polymerase”, Biochemistry, 30:7661-7666,    1991.-   43. Nielsen et al., “Peptide nucleic acids (PNA): oligonucleotide    analogs with a polyamide backbone”, in S. Crooke, B. Lebleu (eds.)    Antisense Research and Applications, Ch 9, CRC Press, Boca Raton,    Fla., pp. 363-373, 1993.-   44. Parisi and Clayton, “Similarity of human mitochondrial    transcription factor 1 to high mobility group proteins”, Science.    262:965-969, 1991.-   45. Parrella et al., “Detection of mitochondrial DNA mutations in    primary breast cancer and fine-needle aspirates”, Cancer Res.,    61:7623-7626, 2001.-   46. Rampino et al., “Somatic frameshift mutations in the BAX gene in    colon cancers of the microsatellite mutator phenotype”, Science,    275:967-969, 1997.-   47. Rantanen et al., “Characterization of the mouse genes for    mitochondrial transcription factors B1 and B2”, Mamm Genome. 14:1-6,    2003.-   48. Ravagnan et al., “Heat-shock protein 70 antagonizes    apoptosis-inducing factor”, Nat Cell Biol. 3:839-843, 2001.-   49. Reed, “Dysregulation of apoptosis in cancer”, J. Clin. Oncol.,    17:2941-2953, 1999.-   50. Rossi, “Practical ribozymes. Making ribozymes work in cells”,    Curr Biol. 4:469-471, 1994.-   51. Sambrook et al., Molecular Cloning. A Laboratory Manual,    (Sambrook, J., Fritsch, E. T. and Maniatis, T. Eds.) 2nd Edn, Cold    Spring Harbor Laboratory, Cold Spring Harbor, N.Y. 1989.-   52. Samejima et al., “CAD/DFF40 nuclease is dispensable for high    molecular weight DNA cleavage and stage I chromatin condensation in    apoptosis”, J Biol Chem. 276:45427-45432, 2001.-   53. Shuey and Attardi, “Characterization of an RNA polymerase    activity from HeLa cell mitochondria, which initiates transcription    at the heavy strand rRNA promoter and the light strand promoter in    human mitochondrial DNA”, J Biol Chem. 260:1952-1958, 1985.-   54. Stephens and Rivers, “Antisense oligonucleotide therapy in    cancer”, Curr. Opin. Mol. Therapeut., 5:118-122, 2003-   55. Summerton, “Morpholino antisense oligomers: a case for an Rnase    H-independent structural type”, Biochim. Biophys. Acta,    1489:141-158, 1999.-   56. Suzuki et al., “A serine protease, Htra2, is <released from the    mitochondria and interacts with xiap, inducing cell death”, Mol.    Cell, 8:613-621, 2001.-   57. Taanman, “The mitochondrial genome: structure, transcription,    translation and replication”, Biochim. Biophys. Acta, 1410:103-123,    1999.-   58. Tan et al., “Comprehensive scanning of somatic mitochondrial DNA    mutations in breast cancer”, Cancer Res., 62:972-076, 2002.-   59. Teitz et al., “Caspase 8 is deleted or silenced preferentially    in childhood neuroblastomas with amplification of MYCN”, Nature Med.    6:529-535, 2000.-   60. Tidd et al., “Oligodeoxynucleotide 5mers containing a 5′-CpG    induce apoptosis through a mitochondrial mechanism in T lymphocytic    leukemia cells,” Nucleic Acids Res., 28:2242-2250 (2000).-   61. Tiranti et al., “Identification of the gene encoding the human    mitochondrial RNA polymerase (h-mtRPOL) by cyberscreening of the    Expressed Sequence Tags database”, Hum Mol Genet. 6:615-625, 1997.-   62. Verhagen et al., “Cell death regulation by the mammalian IAP    antagonist Diablo/Smac”, Apoptosis, 7:163-166, 2002.-   63. Vickers et al., “Efficient reduction of target RNAs by small    interfering RNA and Rnase H-dependent antisense agents”, J. Biol.    Chem., 278:7108-7118, 2003.-   64. Villegas et al., “A novel chimeric mitochondrial RNA localized    in the nucleus of mouse sperm”, DNA & Cell Biol. 19:579-588, 2000.-   65. Villegas et al., “A putative RNA editing from U to C in a mouse    mitochondrial transcript”, Nucleic Acids Res. 30:1895-1901, 2002.-   66. Vogelstein et al., “Surfing the p53 network”, Nature 408:    307-310, 2000.-   67. Wacheck et al., “Small interfering RNA targeting Bcl-2    sensitizes malignant melanoma,” Oligonucleotides 13:393-400, 2003.-   68. Wagner et al., “Nucleotide sequence of the thymidine kinase gene    of herpes simplex virus type 1”, Proc. Natl. Acad. Sci. U.S.A.    78:1441-1445, 1981.-   69. Wahlestedt et al., “Potent and nontoxic antisense    oligonucleotides containing locked nucleic acids”, Proc. Natl. Acad.    Sci. US, 97:5633-5638, 2000.-   70. Warburg, “On the origin of cancer cells”, Science, 123:309-314,    1956.-   71. Wu et al., “Immunofluorescentlabeling of cancer marker Her2 and    other cellular targets with semiconductor quantum dots,” Nature    Biotechnol. 21:4146, 2003.-   72. Yamamoto et al., “Identification of a functional promoter in the    long terminal repeat of Rous sarcoma virus”, Cell 22:787-797, 1980-   73. Yu et al., “Vitamin D receptor expression in human lymphocytes.    Signal requirements and characterization by western blots and DNA    sequencing”, J. Biol. Chem., 266:7588-7595, 1991.-   74. Zaug et al., “A labile phosphodiester bond at the ligation    junction in a circular intervening sequence RNA”, Science,    224:574-578, 1984.-   75. Zörnig et al., “Apoptosis regulators and their role in    tumorogenesis”, Biochim. Biophys. Acta, 1551:F1-F37, 2001.

1. A method comprising the step of inducing at least one of pre-cancercell death or cancer cell death in cells or tissues by contacting atleast one of cancer cells and pre-cancer cells with one or morecompounds or oligonucleotides of 10 to 50 nucleobases in length which issufficiently complementary to a mitochondrial chimeric RNA moleculecomprising: (a) a sense 16S mitochondrial ribosomal RNA covalentlylinked at its 5′ end to the 3′ end of an inverted repeat sequence whichis a segment of an antisense 16S mitochondrial RNA, or (b) the antisense16S mitochondrial RNA, covalently linked at its 5′ end to the 3′ end ofan inverted repeat sequence which is a segment of the sense 16Smitochondrial ribosomal RNA, such that the compounds or oligonucleotidesare able to hybridize with the mitochondrial chimeric RNA molecule toform a stable duplex and thereby induce at least one of pre-cancer celldeath or cancer cell death in cells or tissues.
 2. A method as claimedin claim 1, wherein the mitochondrial chimeric RNA molecule comprises:(a) a human sense 16S mitochondrial ribosomal RNA of SEQ ID NO. 197covalently covalently linked at its 5′ end to the 3′ end of an invertedrepeat sequence which is a segment of a human antisense 16Smitochondrial RNA of SEQ ID NO. 198, or (b) a human antisense 16Smitochondrial RNA of SEQ ID NO. 198, covalently linked at its 5′ end tothe 3′ end of an inverted repeat sequence which is a segment of thesense 16S mitochondrial ribosomal RNA of SEQ ID NO.
 197. 3. A method oftreating a human or animal suspected of having pre-cancer or cancer,comprising the step of administering to said human or animal atherapeutically effective amount of one or more compounds oroligonucleotides of 10 to 50 nucleobases in length which is sufficientlycomplementary to a mitochondrial chimeric RNA molecule comprising: (a) asense 16S mitochondrial ribosomal RNA covalently linked at its 5′ end tothe 3′ end of an inverted repeat sequence which is a segment of anantisense 16S mitochondrial RNA, or (b) the antisense 16S mitochondrialRNA, covalently linked at its 5′ end to the 3′ end of an inverted repeatsequence which is a segment of the sense 16S mitochondrial ribosomalRNA, such that the compounds or oligonucleotides are able to hybridizewith that mitochondrial chimeric RNA molecule to form a stable duplex,to induce at least one of pre-cancer cell death and cancer cell death.4. A method as claimed in claim 3, wherein the mitochondrial chimericRNA molecule comprises: (a) a human sense 16S mitochondrial ribosomalRNA of SEQ ID NO. 197 covalently covalently linked at its 5′ end to the3′ end of an inverted repeat sequence which is a segment of a humanantisense 16S mitochondrial RNA of SEQ ID NO. 198, or (b) a humanantisense 16S mitochondrial RNA of SEQ ID NO. 198, covalently linked atits 5′ end to the 3′ end of an inverted repeat sequence which is asegment of the sense 16S mitochondrial ribosomal RNA of SEQ ID NO. 197.5. The method of claim 1, wherein said step of inducing at least one ofpre-cancer cell death or cancer cell death in cells or tissues isperformed by contacting at least one of cancer cells and pre-cancercells with one or more oligonucleotides of 10 to 50 nucleobases inlength.
 6. The method of claim 5, wherein said one or moreoligonucleotides comprise at least one moiety selected from a modifiedinternucleoside linkage, a modified sugar moiety and a modifiednucleobase.
 7. The method of claim 5, wherein said one or moreoligonucleotides comprises a ribozyme.
 8. The method of claim 7, whereinsaid mitochondrial chimeric RNA molecule comprises a nucleotide sequenceselected from the group consisting of SEQ ID NOS 1-3.
 9. The method ofclaim 7, wherein said mitochondrial chimeric RNA molecule comprises anucleotide sequence selected from the group consisting of SEQ ID NOS4-6.
 10. The method of claim 5, wherein said one or moreoligonucleotides comprises a small interfering RNA.
 11. The method ofclaim 10, wherein said mitochondrial chimeric RNA molecule comprises anucleotide sequence selected from the group consisting of SEQ ID NOS1-3.
 12. The method of claim 10, wherein said mitochondrial chimeric RNAmolecule comprises a nucleotide sequence selected from the groupconsisting of SEQ ID NOS 4-6.
 13. The method of claim 12, wherein saidone or more oligonucleotides comprise at least one moiety selected froma modified internucleoside linkage, a modified sugar moiety and amodified nucleobase.
 14. The method of claim 12, wherein said one ormore oligonucleotides comprises a ribozyme.
 15. The method of claim 14,wherein said mitochondrial chimeric RNA molecule comprises a nucleotidesequence selected from the group consisting of SEQ ID NOS 1-3.
 16. Themethod of claim 14, wherein said mitochondrial chimeric RNA moleculecomprises a nucleotide sequence selected from the group consisting ofSEQ ID NOS 4-6.
 17. The method of claim 12, wherein said one or moreoligonucleotides comprises a small interfering RNA.
 18. The method ofclaim 17, wherein said mitochondrial chimeric RNA molecule comprises anucleotide sequence selected from the group consisting of SEQ ID NOS1-3.
 19. The method of claim 17, wherein said mitochondrial chimeric RNAmolecule comprises a nucleotide sequence selected from the groupconsisting of SEQ ID NOS 4-6.
 20. The method of claim 5, wherein themitochondrial chimeric RNA comprises: (a) a human sense 16Smitochondrial ribosomal RNA of SEQ ID NO. 197 covalently covalentlylinked at its 5′ end to the 3′ end of an inverted repeat sequence whichis a segment of a human antisense 16S mitochondrial RNA of SEQ ID NO.198, or (b) a human antisense 16S mitochondrial RNA of SEQ ID NO. 198covalently linked at its 5′ end to the 3′ end of an inverted repeatsequence which is a segment of the sense 16S mitochondrial ribosomal RNAof SEQ ID NO.
 197. 21. The method of claim 20, wherein the one or moreoligonucleotides comprise a nucleotide sequence selected from the groupconsisting of SEQ ID NOS 9-196.
 22. The method of claim 5, wherein theone or more oligonucleotides comprise antisense oligonucleotides. 23.The method of claim 22, wherein said mitochondrial chimeric RNAcomprises a nucleotide sequence selected from the group consisting ofSEQ ID NOS 1-6.
 24. The method of claim 22, wherein said mitochondrialchimeric RNA molecule comprises a nucleotide sequence selected from thegroup consisting of SEQ ID NOS 1-3.
 25. The method of claim 22, whereinsaid mitochondrial chimeric RNA molecule comprises a nucleotide sequenceselected from the group consisting of SEQ ID NOS 4-6.
 26. The method ofclaim 2, wherein said mitochondrial chimeric RNA molecule comprises anucleotide sequence selected from the group consisting of SEQ ID NOS1-3.
 27. The method of claim 2, wherein said mitochondrial chimeric RNAmolecule comprises a nucleotide sequence selected from the groupconsisting of SEQ ID NOS 4-6.
 28. The method of claim 3, wherein saidcompounds or oligonucleotides are administered in conjunction with achemotherapeutic drug for the treatment of cancer.
 29. A method asclaimed in claim 28, wherein said combination of said compounds oroligonucleotides and said chemotherapeutic drug for the treatment ofcancer is capable of inducing a more effective cancer cell death thansaid chemotherapeutic drug for the treatment of cancer, whenadministered alone.
 30. The method of claim 3, wherein said step ofadministering is performed by administering to said human or animal atherapeutically effective amount of one or more oligonucleotides of 10to 50 nucleobases in length.
 31. The method of claim 30, wherein the oneor more oligonucleotides comprise antisense oligonucleotides.
 32. Themethod of claim 31, wherein said mitochondrial chimeric RNA comprises anucleotide sequence selected from the group consisting of SEQ ID NOS1-6.
 33. The method of claim 31, wherein said mitochondrial chimeric RNAmolecule comprises a nucleotide sequence selected from the groupconsisting of SEQ ID NOS 1-3.
 34. The method of claim 31, wherein saidmitochondrial chimeric RNA molecule comprises a nucleotide sequenceselected from the group consisting of SEQ ID NOS 4-6.
 35. The method ofclaim 30, wherein said mitochondrial chimeric RNA comprises a nucleotidesequence selected from the group consisting of SEQ ID NOS 1-6.
 36. Themethod of claim 35, wherein the one or more oligonucleotides comprise anucleotide sequence selected from the group consisting of SEQ ID NOS9-196.
 37. The method of claim 4, wherein said mitochondrial chimericRNA molecule comprises a nucleotide sequence selected from the groupconsisting of SEQ ID NOS 1-3.
 38. The method of claim 4, wherein saidmitochondrial chimeric RNA molecule comprises a nucleotide sequenceselected from the group consisting of SEQ ID NOS 4-6.
 39. The method ofclaim 4, wherein said mitochondrial chimeric RNA molecule comprises thesequence of SEQ ID NO
 1. 40. The method of claim 4, wherein saidmitochondrial chimeric RNA molecule comprises the sequence of SEQ ID NO2.
 41. The method of claim 4, wherein said mitochondrial chimeric RNAmolecule comprises the sequence of SEQ ID NO
 3. 42. The method of claim4, wherein said mitochondrial chimeric RNA molecule comprises thesequence of SEQ ID NO
 4. 43. The method of claim 4, wherein saidmitochondrial chimeric RNA molecule comprises the sequence of SEQ ID NO5.
 44. The method of claim 4, wherein said mitochondrial chimeric RNAmolecule comprises the sequence of SEQ ID NO
 6. 45. The method of claim1, wherein said contacting step does not induce apoptosis in normalcells.
 46. The method of claim 3, wherein said contacting step does notinduce apoptosis in normal cells.